Terahertz Sensing Technology

Michael Shur CIE, ECSE, Physics, and Center for THz Research Rensselaer Polytechnic Institute http://nina.ecse.rpi.edu

IEEE Sensors Conference October, 2008 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 1 I am grateful to my THz colleagues for their hard work, inspiration, and contributions

Dr. Rumyantsev Dr. Knap Dr. Dyakonova and Dr. Veksler Dr. Kachorovskii Prof.Pala Prof. Dyakonov

Dr. Stillman Prof. Zhang Prof. V. Ryzhii Dr. Dmitriev Dr.Deng Prof. M. Ryzhii

Dr. Muraviev Dr. Satou Dr. Levinshtein Dr. Popov THz Center at RPI led by Prof. Zhang

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 2 Tutorial Outline

•History •Applications •Terahertz Photonics •Terahertz Electronics •Plasma wave electronics •Terahertz properties of grainy multifunctional materials •Conclusions and future work

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 3 Tutorial Outline History •Applications •Terahertz Electronics •Terahertz Photonics •Plasma wave electronics •Terahertz properties of grainy multifunctional materials •Conclusions and future work

From http://www.phys.uu.nl/~vgent/astronomia_large.jpg

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 4 Human Civilization and Electromagnetic Spectrum Visible Spectrum

To Edison bulb To the To gas lighting 1879 first candle 1772 1,000 BC

To the first torch 500,000 Soon to be replaced by LEDs years ago Solid State Lighting

From using Sun Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 5 Moving to shorter and longer wavelengths in the 19-th and 20-th century

•Radio 1 – 108 m (1936) •Radar 10-1 – 1 m (1936) Cell phone (1973) •Terahertz Gap (10 μm – 1 mm) •IR •Incandescent 4 10-7 –7.6 10-7 m (1901) LEDs (1961) •UV 10-7 –4 10-7 m (1901) •X-ray 10-14 –10-7 m (1895)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 6 From tryshotcode.com/terahertz1.aspx

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 7 T-rays

From: http://www.advancedphotonix.com/ap_products/images/prods_Terahertz_graphLarge.jpg Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 8 Synonyms

•Big and large •buy and purchase (verb) •Car and automobile •THz, submillimeter and far-infrared

•1 THz -> 300 μm -> 4.3 meV ->33 cm-1

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 9 Tutorial Outline

•History •Applications

•Terahertz Photonics Comet Iras-Araki-Alcock. Image is taken at 12 THz

Courtesy of Infrared Processing and Analysis •Terahertz Electronics Center, Caltech/JPL. IPAC is NASA's Infrared •Plasma wave electronics Astrophysics Data Center •Terahertz properties of grainy multifunctional materials •Carbon THz electronics and photonics •Conclusions and future work

From : www.burbankwire.com/fbi_advisory.shtml

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 10 THz Applications

•Radio astronomy http://science.hq.nasa.gov/missions/satellite_22.htm •Earth remote sensing •Vehicle radars and compact radars •Non-destructive testing •Chemical analysis •Explosive detection From http://24hoursnews.blogspot.com/2007_09_24_archive.html •Moisture content determination •Coating thickness control •Imaging •Film uniformity •Structural integrity •Wireless covert communications •Medical applications •Concealed weapons detection

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 11 Privacy Concerns?

•The machine creates a 3-d image of the passenger's body then sends it to a viewing station in another room where a TSA agent looks for potential threats. • "It's passenger imaging technology, so it allows us to see the entire image of the passenger's body and anything that might be hidden on the person" said Ellen Howe of TSA. • The new technology includes new privacy protection also. The screener in the viewing room can't see the passenger's face and the images from the machine are deleted, once the traveler is cleared to fly.

From http://24hoursnews.blogspot.com/2007_09_24_archive.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 12 IRAM interferometer (Plateau de Bure, French Alps)

•Started in 1985 •6 antennas of 15 meters diameter •Wavelength of 1.3 mm (230 GHz) •Antennas of the IRAM interferometer can move on rail tracks up to a maximum separation of 408 m in the E-W direction and 232 m in the N-S direction From Pierre ENCRENAZ & Gérard •Resolution of 0.5 arcsecs BEAUDIN Recent developments in (resolving an apple at a millimeter and submillimeter waves. http://gemo.obspm.fr/ArticleLigne/Re distance of 30 km). centDvlp.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 13 CONDOR (1.5 THz heterodyne receiver) at APEX (Atacama Pathfinder EXperiment) in Chilean Andes

Detected hot gas 11/2005 in the vicinity of young massive stars. The THz atmospheric windows centered at 1.3 and 1.5~THz contain spectral lines of including CO lines, the N+ line at 205 microns, and the ground

transition of para- http://www.sciencedaily.com/images/2005/12/051227155401.jpg H2D+. Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 14 Why THz telescope is in Chile

From www.submm.caltech.edu/cso/cso_submm.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 15 Stratospheric Observatory For Infrared Astronomy (SOFIA). Using CONDOR on SOFIA.

747 airplane with an infrared telescope inside

From http://www.etsu.edu/physics/bsmith/variable/sofia.gif Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 16 THz detects cold matter (140 K or less), such as clouds of gas and dust in our and nearby galaxies. New stars beginning to form radiate heat as they contract and are clearly seen in the THz range. Stars invisible in a dense cloud of dust appear as very bright stripe in the THz image because they heat the dust that glows in far-infrared

[5] http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/images/iras_cirrus.jpg [6] http://www.esa.int/esaSC/Pr_1_2002_s_en.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 17 Infrared Astronomical Satellite (IRAS) in its 560- mile-high, near-polar orbit above the Earth

Comet Iras-Araki-Alcock was discovered by (IRAS). Image is taken at 25 micron (12 THz)

Courtesy of Infrared Processing and Analysis Center, Caltech/JPL. IPAC is NASA's Infrared Astrophysics Data Center

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 18 COBE – Cosmic Background Explorer

•Far Infrared Absolute Spectrophotometer (FIRAS) measuring the spectrum of cosmic microwave background radiation (CMBR) •Differential Microwave Radiometers (DMR) detecting faint fluctuations in CMBR •Diffuse Infrared Background Experiment (DIRBE) obtaining data on cosmic infrared background, structure of Milky Way and interstellar dust.

From http://lambda.gsfc.nasa.gov/product/cobe/slide_captions.cfm Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 19 Aura spacecraft: Earth Atmosphere Monitoring

•The Aura spacecraft was launched into a near polar, sun-synchronous orbit with a period of approximately 100 minutes. The spacecraft repeats its ground track every 16 days to provide atmospheric measurements over virtually every point on the Earth in a repeatable pattern, permitting assessment of atmospheric phenomena changes in the same geographic locations throughout the life of the mission.

From http://aura.gsfc.nasa.gov/spacecraft/index.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 20 Microwave Limb Sounder From http://mls.jpl.nasa.gov/joe/Aura_pre-launch_MLS_9- charts.pdf

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 21 Environmental Control: Ozone Hole

From: http://www.jpl.nasa.gov/news/news.cfm?release=2004-291 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 22 Development of Ozone Hole

http://science.hq.nasa.gov/missions/satellite_22.htm

One out of five Americans will develop cancer over their lifetime

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 23 Vehicle Radar

From http://www.ntu.edu.sg/home/eadams/IROS_2005_tutorial/dsta_vehicle+radar.JPG

From http://www.uml.edu/media/enews/print_1_108961_108961.html

http://www.virtualacquisitionshowcase.com/thumbs/vas_323.jpg

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 24 Compact Radar Range

Tank model From stl.uml.edu/research/radar.html

stl.uml.edu/research/sub_9.html Dielectrically scaled trees

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 25 Scientific Investigations

Exploring THz Spectroscopy: Technology and applications in the field of dynamics and nanostructures International Bunsen Discussion Meeting Bad Honnef, April 1-4, 2007 W. van der Zande (Radbout University, Nijmegen) A narrow band high intensity light source from 0.3 to 3 THz: a free electron laser M. Hofmann (Ruhr-Universität Bochum) Diode laser based THz technology N. Hiromoto (Shizuoka University, Japan): Terahertz remote sensing in the living space D. Leitner (University of Nevada at Reno, USA) Dynamics and THz absorption of protein hydration water

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 26 Non-destructive testing of materials and electronic devices

From: www.navyopportunityforum.com/abstracts.php?on.. Abstract # 20

GMA Industries, Inc. Terahertz Imaging System for Composite Material Assessment Composites, non-destructive inspection, defects, foreign object debris, fiberglass, Kevlar, ceramic

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 27 Space Shuttle Foam Inspection

•After the Space Shuttle Columbia disaster in 2003, NASA started examining the shuttle fuel tank using the Picometrix QA1000.

Image from: http://www.advancedphotonix.com/ap_products/thz_app_sofi.asp

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 28 Space Shuttle Tile Inspection

Image from http://www.advancedphotonix.com/ap_products/thz_app_tiles.asp

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 29 Black Body and THz Radiation

-7 ) 10 -1 Sun •Hz -1 T= 6500 K •sr

-2 10-9 •m -1 (J•s

10-11

Earth -13 10 T=300 K

-15

Spectral radiance Spectral radiance 10 0.1 1 10 100 1000 Frequency (THz) Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 30 Maximum emission wavelength and frequency

106

105 Wavelength (nm) 104

1000

100 Frequency (THz)

1 10 50 100 500 1000 5000 Temperature (K)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 31 Emissivity

4 http://www.spectrum.ieee.org/images/jul07/images/tray01.jpg j = εσT Power per unit area

Stefan’s constant ε is emissivity (1 for black body (i.e. for the Sun))

Passive imaging picks up differences in surface temperature and emissivity

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 32 Communications: Optical fiber transmission

(Adapted from Streetman, Solid State Electronic Devices)

Δf=10 THz

Diminished Rayleigh Scattering at THz frequencies (1/λ4)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 33 Near-field THz microscopy

Courtesy Prof. R. Kersting Challenge: Wavelength of 1 THz: λ = 300 μm Ö Scanning Near-field Optical Microscope (SNOM) Here: Detection of specularly reflected light Metal grating:

H.-T. Chen, G.C. Cho, and R. Kersting. Appl. Phys. Lett. 83, 3009 (2003).

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 34 Spatial Resolution

Courtesy Professor R. Kersting Edge mapped at constant height:

10.0 8.0 6.0 metal semicond. Results: 4.0 (air) 2.0 • achieveable resolution: 150 nm Current [nA] 0.0 (with a 100 nm tip) 150 nm 112.8 But: 112.7 • unexpected high image contrast (> 10-3) 112.6 • unexpected image polarity

112.5 112.4 THz Signal [nA] 112.3 112.2 41.0 41.5 42.0 42.5 43.0 43.5 44.0 Position [μm] H.-T. Chen, G.C. Cho, and R. Kersting. Appl. Phys. Lett. 83, 3009 (2003). Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 35 Concealed Weapon Detection

THz Image of a Man Carrying a Gun

http://www.spectrum.ieee.org/images/jul07/images/tray01.jpg

From http://www.scenta.co.uk/_db/_images/terahertz_radiation140.jpg

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 36 More Images

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 37 Seeing inside packages

A THz image of a shipping box filled with packing material contained a plastic knife and a razor blade.

Image from:http://www.advancedphotonix.com/ap_products/thz_app_packageimage.asp Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 38 THz wireless covert communications

From: http://www.atl.lmco.com/business/ATL7.php

Difficult on Earth (water vapors) – 100’s m max? First generation SYNCOM satellite Possible in space (NASA image)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 39 High Resolution Imaging (200 micron resolution)

Image from: http://www.advancedphotonix.com/ap_products/thz_app_hiresimage.asp

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 40 THz Applications in Medicine

3D Graph of demineralized tooth

From http://www.teraview.co.uk/ab_ imageLibrary.asp?page=3#

From http://www.ist-optimist.org/pdf/network/pres_ecoc2002/TERAVISION_ECOC2002.pdf Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 41 Medical Applications: Skin Cancer Imaging

http://www.teraview.co.uk/ab_imageLibrary.asp?page=3# Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 42 Avoid Multiple Breast Cancer Surgeries by Terahertz Imaging

From www.straightfromthedoc.com/50226711/

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 43 Prostate Cancer

•The most common cancer among men •230,000 new cases a year diagnosed •Autopsy studies of Chinese, German, Israeli, Jamaican, Swedish, and Ugandan men men who died of other causes revealed prostate cancer in thirty percent of men . •But how? –PSA – controversial test –Biopsy – if positive, you do have cancer –If negative – you either do not have it or it has missed your cancer

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 44 Prostate Cancer Detection by T-rays

0.50 (1) 10-22-03 (2) 10-22-03 (3) 10-30-03 0.50 0.36 0.48 (4) 11-13-03 CC895, liquid CC896, frozen 0.48 CC896 0.34 0.46 0.46 0.32

0.44 0.44 0.30 Transmission 0.42 0.42 Transmission 0.28

0.40 0.40 CC895 0.26 0.38 10 12 14 16 18 20 22 24 0.24 10 12 14 16 18 20 22 24 Frequency, cm-1 Frequency, cm-1 Long term reproducibility of transmission Liquid and frozen samples measured spectra of prostate cancer cells measured at close orientation have a similar pattern. after storage of the sample in frozen condition for several weeks. From T. Globus, D. Theodorescu, H. Frierson , T. Kchromova , D. Woolard, “Terahertz spectroscopic characterization of cancer cells”, presented at SPIE Conference “Advanced Biomedical and Clinical Diagnostic Systems III”, San-Jose, January 2005, Proceedings V. 5692-42, and published in Progress in Biomedical Optics and Imaging, Vol 6, No7, p 233-240, 2005, by permission

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 45 A mouse prostate section with tumor tissue (circle) as imaged with terahertz, optical, and staining techniques

After Peter Siegel, www.nibib.nih.gov/HealthEdu/eAdvances/21June06 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 46 THz Spectrum of Sugar

From http://oldwww.com.dtu.dk/research/Nanophotonics/sugarspectrum_small.png

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 47 Explosive Detection: Number of Suicide Attacks per Year

500

400

300

200

100

0 1981-1990 1991-2000 2001-2003 2004(est.)

From (data for 1981-2003 are from Y. Chen, H. Liu, M. J. Fitch, R. Osiander, J. B. Spicer, M. Shur, X. -C. Zhang, THz Diffuse Reflectance Spectra of Selected Explosive and Related Compounds, SPIE, Florida NATO Science, Society, Security News, No 68, p. 3, provided to NATO by Dr. Scott Atran

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 48 Suicide Bombings in Iraq 2003- October 15 2007

Picture from yaleglobal.yale.edu/article.print?id=3749

From www.motherjones.com/news/feature/2007/11/iraq...

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 49 THz Explosive Detection

Y. Chen, H. Liu, Haibo; M. J. Fitch, Rosined, J. B. Spicer, M. S. Shur, X. C. Zhang, THz diffuse reflectance spectra of selected explosives and related compounds, Passive Millimeter-Wave Imaging Technology VIII. Edited by Appleby, Roger; Wikner, David A. Proceedings of the SPIE, Volume 5790, pp. 19-24 (2005)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 50 THz applications – recent reminder

From www.crimelibrary.com/.../anthrax/3.html 2001

2008

Army scientist Bruce E. Ivins

From http://www.wkrg.com/national/article/suicide_latest_twist_in_7_year_anthrax_saga/16504/

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 51 Terahertz Detection of Biological Agents

From http://www.rensselaer.edu/~zhangxc/abouthome.htm

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 52 THz active scanners in airports

Adding THz scanning to this airport ion mass spectrometer sensor will reduce the number of false alarms and will test under clothing

From Valerie J. Brown T Rays vs. Terrorists: Widening the Security Spectrum Environmental Health Perspectives Volume 114, Number 9, September 2006

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 53 Tutorial Outline

•History •Applications •Terahertz Photonics •Terahertz Electronics •Plasma wave electronics •Terahertz properties of grainy multifunctional materials •Conclusions and future work

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 54 Terahertz Photonics •Sources Broadband radiation –Photo-Dember Effect –Current Transient (Austin switch – higher power) –Optical Rectification (larger band width) Femtosecond radiation –Quantum Cascade Lasers •Detectors –Current Transient (Austin switch)

Electrons (red) diffuse deeper into semiconductor, then come back to recombine with holes (blue)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 55 Quantum Cascade Laser

Energy

Distance R. F. Kazarinov and R. A. Suris Sov. Phys. Semicond. v.5, #4, pp.707-709 (1971)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 56 THz QCL

B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, "Operation of terahertz quantum-cascade lasers at 164 K in pulsed mode and at 117 K in continuous-wave mode," Optics Express, 13, 3331-3339 (2005) 3 THz at 164 K

QCL

From http://images.pennnet.com/articles/lfw/thm/th_0607lfwn2.jpg

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 57 Quantum Cascade Laser

From B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, "Operation of terahertz quantum-cascade lasers at 164 K in pulsed mode and at 117 K in continuous-wave mode," Optics Express, 13, 3331-3339 (2005)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 58 Room Temperature THz laser

Mikhail Belkin and Federico Capasso

APL, May 19, 2008

A photograph of a bar with 10 terahertz laser sources developed by the Harvard University engineers. One of the lasers is connected to the contact pad (seen on the left) by two thin gold wires. A 2mm-diameter Silicon hyper-hemispherical lens is attached to the facet of the device to collimate the terahertz output. The emission frequency is 5 THz, corresponding to a wavelength of 60 microns. (Credit: Courtesy of the Capasso Lab, Harvard School of Engineering and Applied Sciences) Harvard University (2008, May 20). First Room-temperature Semiconductor Source Of Coherent Terahertz Radiation Demonstrated. ScienceDaily. Retrieved August 29, 2008, from http://www.sciencedaily.com- /releases/2008/05/080519083023.htm

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 59 THz Imaging with Quantum Cascade Laser

From J. Darmo, V. Tamosiunas, G. Fasching, J. Kroll, K. Underainer, M. Beck, M. Giovannini, and J. Faist, Optics Express, vol. 12, No. 9, p.1879 (2004) Courtesy of Professor Underainer Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 60 Optical Rectification

PEE =+ α βγ23 + E + .

22 Pxxo =+ αEtEt cos (ωβ ) xo cos ω ( ) 1cos+ (2ω t ) cos2 (ω t ) = 2

DC (i.e. low frequency) component contains THz frequencies due to the fs laser pulse waveform

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 61 Photoconducting Current (Austin Switch)

∂j E = THz ∂t 22 2 1 qa PNTHz =Δ 3 6πε o c ΔN number of electrons

q electronic charge Grischkowsky antenna c speed of light a acceleration ε o vacuum dielectric permittivity

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 62 Why Si Lens? THz (0.2 – 2 THz) index of refraction and power absorption

Material Index of Power Refraction Absorption (cm- 1) Fused silica 1.952 1.5

Sapphire no =3.070; 1 ne=3.415 Intrinsic Ge 4.002 0.5 High-res GaAs 3.595 0.5

Quartz no =2.108; 0.1 ne=2.156 High-res Si 3.418 0.05

Data from:

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 63 Photo-Dember Effect

Effective in narrow band-gap with large electron mobility and low hole mobility (InSb, InN).

Femtosecond radiation

Electrons (red) diffuse deeper into semiconductor, then come back to recombine with holes (blue)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 64 THz Pulse in Time and Frequency Domain

Courtesy of Professor X. C. Zhang, RPI Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 65 THz Photonics: Time Domain THz Spectroscopy

Mainstream

From www.brucherseifer.com/html/projects.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 66 Photomixing

•Modulated infrared radiation can cause the resonant excitation of plasma oscillations in quantum well diode and transistor structures •This effect provides a new mechanism for the generation of tunable terahertz radiation •We developed a device model for a quantum well photomixer* •The proposed device can significantly surpass standard quantum well infrared photodetectors. * ======

* After V. Ryzhii, I. Khmyrova, and M. S. Shur, Terahertz photomixing in quantum well structures using resonant excitation of plasma oscillations, J. Appl. Phys. Vol. 91, pp. 1875 (2002)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 67 Resonant Photomixer

V. Ryzhii, A. Satou, I. Khmyrova, M. Ryzhii, T. Otsuji, and M. Shur, “Analytical and computer models of terahertz HEMT-photomixer,” SPIE, Conference on Microwave and Terahertz Photonics, Vol. 5466, pp. 210-217, Strasbourg, April 2004

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 68 Experimental Observation of Resonant Photomixing

p. 2119

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 69 THz systems (a) TeraView’s TPI imaga 2000: 3D THz imaging system for tablet coatings and cores (b) Picometrix

(a) (b)

From http://www.pharmaceutical-technology.com/contractor_images/teraview/1s-terraview.jpg From http://www.advancedphotonix.com/ap_products/terahertz.asp Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 70 Compact THz Photonics System –Mini-Z

2007 $30,000 Lemelson-Rensselaer Student Prize.

Brian Schulkin (RPI, graduate student of Professor Zhang) has invented an ultralight, handheld terahertz spectrometer

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 71 Some of the THz Companies

Coherent, Inc Fs lasers, optically pumped THz lasers www.CoherentInc.com

Picometrics THz imaging (THz photonics) www.picometrics.com

Teraview LTD THz imaging (THz photonics) www.teraview.co.uk

Virginia Diodes, Inc.Schottky diode multipliers www.virginiadiodes.com

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 72 Free Electron laser

∂j E = THz ∂t 22 γ 241πε qa PNTHz =Δ 3 γ 6 o c ratio of mass to rest mass (20) ΔN number of electrons q electronic charge c speed of light a accelerationε

o vacuum dielectric permittivity

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 73 Jefferson Lab facility spectroscopic range

Energy (meV) 1 10 100 1000 10000 1000 JLab FEL 100 JLab THz 10 1 )

1 FEL proof of principle: - 0.1 0.01 Table-top sub-ps Neil et al. Phys. 1E-3 lasers Rev.Letts 84, 662 1E-4 (2000) ons 1E-5Synchrotr 1E-6 1E-7

Flux (Watts/cm Flux 1E-8 Courtesy 1E-9 of G.P. Williams THz proof of principle: 1E-10 Carr, Martin, McKinney, Neil, Jordan & Williams Jefferson Lab 1E-11 Nature 420, 153 (2002) 1E-12 r 1ba 10 100 1000 10000 o -1 Gl Wavenumbers (cm )

Operated by the Southeastern Universities Research Association for the U.S. Department ofThomas Energy Jefferson National Accelerator Facility

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 74 Free electron laser

From http://www.jlab.org/FEL/images/FELdiagram.gif

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 75 Jefferson Lab Free Electron Lasers

•Wavelength range (IR)1-14μm •Power/pulse 20 μJ Pulse From: http://www.jlab.org/FEL/terahertz/ •Repetition frequency up to 75 MHz •Pulse length 500-1700 fs •Maximum average power>10 kW •Wavelength range (UV/VIS)250-1000 nm •Power/pulse 20 μJ •Pulse repetition frequency up to 75 MHz •Pulse length300-1700 fs •Maximum average power>1 kW Gwyn Williams holding a 5-cell cavity inside JLab's FEL Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 76 CPU speed versus time

From D. A. Muller, A sound barrier for silicon? Nature Materials, 4, pp. 645-647 (2005).

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 77 VLSI Technology Limits: Moore No More

Transistors per chip 2015 10 billion 2009 2018 2006 1 billion Monte-Cito 100 million 2006 1.6 109 transistors Itanium 2

10 million Itanium 1 million Pentium

0.1 million 316

4004 (2300 transistors)

1971 19902000 2010 2020 Year

After http://www.indybay.org/uploads/2006/05/18/moore__sl_small.jpglsjprm.jpg

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 78 Tutorial Outline

•History •Application examples •Terahertz Photonics •Terahertz Electronics •Plasma wave electronics •Terahertz properties of grainy multifunctional materials •Conclusions and future work

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 79 Terahertz Electronics

•Sources – Two terminal devices •IMPATT •Gunn – Transistors •HEMTs •HBTs 30 •Heterodimensional Transistors and FinFETs 400 – Plasma Wave Electronics emitters (laboratory stage) – Graphene THz lasers (proposed by V. Ryzhii) •Detectors From W.J. Stillman and M.S. Shur, Closing the Gap: – Schottky diodes Plasma Wave Electronic – Pyroelectric detectors Terahertz Detectors, Journal of Nanoelectronics – Hot electron bolometers and Optoelectronics, Vol. 2, – Plasma Wave Detectors Resonant Detectors Number 3, pp. 209-221, •Nonresonant December 2007 – Carbon nanotubes (proposed)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 80 THz gap

From W.J. Stillman and M.S. Shur, Closing the Gap: Plasma Wave Electronic Terahertz Detectors, Journal of Nanoelectronics and Optoelectronics, Vol. 2, Number 3, pp. 209-221, December 2007

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 81 Schottky Diode Tripler

Courtesy of Virginia Diodes, Inc. Reproduced with permission

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 82 Schottky Diode Multiplication

Courtesy of Virginia Diodes, Inc. Reproduced with permission.

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 83 Schottky Diode Quintupler

Courtesy of Virginia Diodes, Inc. Reproduced with permission

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 84 Resonant Tunneling Diodes

(Color online) Fundamental structure of the RTD oscillator . (a) Slot resonator and RTD, (b) potential profile and current– voltage characteristics of RTD, and (c) equivalent circuit of (a).

Fundamental oscillation up to 0.65 THz and harmonic oscillation up to 1.02 THz

From Masahiro ASADA, Safumi SUZUKI, and Naomichi KISHIMOTO “Resonant Tunneling Diodes for Sub-Terahertz and Terahertz Oscillators” Expected up to 60 microwatt at 2 THz Japanese Journal of Applied PhysicsVol. 47, No. 6, 2008, pp. 4375–4384

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 85 CPU Clock Speed versus Year

2,000 Military 1,000 700 500 Commercial 300 200 Sound barrier Speed (mph) Speed 100

1920 1940 1960 1980 2000 2020

Year

From http://ask.metafilter.com/78227/

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 86 45nm IBM Si NMOS and PMOS using a notched body contact

From Sungjae Lee, Basanth Jagannathan*, Shreesh Narasimha*, Anthony Chou*, Noah Zamdmer*, Jim Johnson, Richard Williams, Lawrence Wagner*, Jonghae Kim*, Jean-Olivier Plouchart*, John Pekarik, Scott Springer and Greg Freeman, Record RF performance of 45-nm SOI CMOS Technology, IEDM Technical Digest, p. 225 (2007)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 87 Northrop Grumman fmax is higher than 1 THz

From R. Lai, X. B. Mei, W.R. Deal, W. Yoshida, Y. M. Kim, P.H. Liu, J. Lee, J. Uyeda, V. Radisic, M. Lange, T. Gaier, L. Samoska, A. Fung, Sub 50 nm InP HEMT Device with Fmax Greater than 1 THz, IEDM Technical Digest, p. 609 (2007)

InGaAs/InP Based HEMT

35 nm gate device cross section

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 88 HRL 300 GHz MMIC

From: http://www.hrl.com/html/techs_mel.html

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 89 Velocity-Field Curves for III-N Family

InN is the fastest nitride material

Red Line – v(E) for InAs (from Hess and Brennan (1984), See M.P. Mikhailova Handbook Series on Semiconductor Parameters, vol.1, M. Levinshtein, S. Rumyantsev and M. Shur, ed., World Scientific, London, 1996, pp. 147-168.

From B. E. Foutz, S. K. O'Leary, M. S. Shur, and L. F. Eastman, J. Appl. Phys. 85, 7727 (1999)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 90 Higher velocity in short devices - overshoot

InN – higher overshoot at smaller fields

From B. E. Foutz, S. K. O'Leary, M. S. Shur, and L. F. Eastman, J. Appl. Phys. 85, 7727 (1999)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 91 Calculated Cutoff Frequency

Monte Carlo

Channel length (micron)

From S. K. O'Leary, B. E. Foutz, M. S. Shur, and L. F. Eastman, Potential Performance of Indium-Nitride-based Devices, Appl. Phys. Lett. 88, 152113 (2006)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 92 Cutoff frequency and effective velocity GaN 140 f (GHz) 120T Oktas et al (1997) Ping et al (1998) 100 Chen et al (1996) Kumar et al (2002) 80 Wu et al (2001) 5 vhighest = 1.39 10 m/s Shen et al (2001) 60 Ping et al (1998) 40 Youn et al (2004) 5 20 vaverage = 1.11 10 m/s 0 0123456 7 Inverse effective gate length (1/ m) From M. S. Shur and R. Gaska, Physics of GaN-based Heterostructure Field Effect Transistors, 2005 IEEE CSICS Technical Digest, Palm Springs, CA, pp. 137-140, ISBN 0-7803-9250-7 RECORD!

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 93 60 nm GaN-HEMT from Fujitsu

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 94 Nitride Problem: Effective Gate Length

• THz-range transistors require gate electrodes with deep submicron-length • Effective gate length significantly 150 nm gate exceeds the physical gate length • As a result, high cut-off frequencies can only be achieved at low drain bias > low RF- powers • At high drain bias effective gate From V. Turin, M. Shur, D. Veksler, length increases > lower cut-off International Journal of High Speed Electronics frequencies and Systems, vol. 17, No. 1, 19, 2007

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 95 EFFECTIVE GATE LENGTH After V. O. Turin, M. S. Shur, and D. B. Veksler, IJHSES, vol. 17, No. 1, 19, 2007

Distribution of electron velocity in the channel under the gate (1 nm below AlGaN-GaN interface)

Distribution of electric field in the channel under the gate

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 96 Drain Field Controlling Electrode (FCE)

FCE From V. Turin, M. Shur, D. Veksler, International Journal of High Speed Electronics and Systems, March 2007

FCE connected to the drain with small gap between the gate can be used to influence electron velocity distribution in channel that, in turn, can improve the cutoff frequency.

After V. O. Turin, M. S. Shur, and D. B. Veksler Simulations of field-plated and recessed gate gallium nitride-based heterojunction field-effect transistors, International Journal of High Speed Electronics and Systems, vol. 17, No. 1 pp. 19-23 (2007)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 97 Field Controlling Electrode Implementation

After Pala, N. Yang J., Z. Koudymov, A. Hu, X. Deng, J. Gaska, R. Simin, G. Shur, M. S. Drain-to-Gate Field Engineering for Improved Frequency Response of GaN-based HEMTs, Device Research Conference 2007 65th Annual, 18-20 June 2007, pp. 43-44 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 98 Improvement of fT

60 Lg=0.3 μm

, GHz 57 T f no FCE 54 D =0.5μm G-FCE D =0.7μm 51 G-FCE 10 15 20 25 30 Drain bias, V

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 99 Problem: Access Resistances

• THz-range transistors require highest possible RF transconductance. • Source resistance drastically I R , R = 0 reduces the transconductance of D S D R 2 A/mm devices with sub-mm long gate. D G Hence extremely low contact and source-gate access resistances RS R , R <> 0 are required. S S D • Annealed contacts do not allow 3 V V for short source – drain spacing From G. Simin, Wide Bandgap Devices with and have relatively high contact Non-Ohmic Contacts, 210th Electrochemical Society Meeting 2006, Cancun, Mexico resistance October 29-November 3, 2006

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 100 High fmax/ft are possible with high Rs using capacitive (C^3)contacts

First evidence: Rs was 10 ohm-mm! Contacts were RC type (Schottky)

From J. Burm, K. Chu, W. J. Schaff, L. F. Eastman, M. A. Khan, Q. Chen, J. W. Yang, and M. S. Shur 0.12-µm Gate III-V Nitride HFET's with High Contact Resistances, IEEE Electron Device Letters, Vol. 18, No. 4, pp. 141-143, April (1997)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 101 PROPOSED SOLUTION – C^3 CONTACTS + MIS

SG D Metal AlGaN L AlGaN GaN 2DEG GaN

1.6 1.4 15 μm 1.2 m 1.0 -m

Ω Measured 0.8 , 0.6 CEq 7 μm R 0.4 L=3 μm 0.2 0 10203040 Frequency, GHz From Simin, G., Yang, Z-J. Shur, M.,, Microwave Symposium, 2007. IEEE/MTT-S 3-8 June 2007 pp. 457-460, ISSN: 0149-645X, ISBN: 1-4244-0688-9

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 102 PROPOSED SOLUTION – C^3 CONTACTS

SDG 1 0.9 0.8 20 GHz AlGaN 0.7 -mm

Lext Lext Ω 0.6 , GaN 0.5

CEff 0.4 50 SiC R 0.3

0.2 100

0.1 0 0.5 1 1.5 2

Lext, μm Self-aligned C3 electrodes written and deposited simultaneously with gate

From G. Simin, Wide Bandgap Devices with Non-Ohmic Contacts, 210th Electrochemical Society Meeting 2006, Cancun, Mexico October 29-November 3, 2006

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 103 Si02/AlGaN/GaN Devices (MOSHFETs)

SiO 2 (200-300A)

S G D

1500 AlGaN barrier (200 A) Vgs = +9V +6 V 1000 +3 V GaN channel 0 V

AlN Buffer 500

Ids(mA/mm) -3 V

-6 V -9 V I-SiC 0 0 1020304050 Vds(V)

From “AlGaN-GaN metal–oxide–semiconductor heterostructure field-effect transistors on SiC substrates” M. Asif Khan, X. Hu, A. Tarakji,G. Simin, and J. Yang, R. Gaska and M. S. Shur, APL 2000

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 104 HFET, MOSHFET, and MISHFET

Si3N4 SG D Pd/Ag/AuPd/Ag/Au Currents up to 2.5 A/mm AlInGaN Demonstrated GaN AlN Leakage down by 10^6 I-SiC 600 1x10-4 MOSHFET - SiO (ε = 3.9, 100 A) 500 2 1x10-6 HFET MISHFET - Si3N4 (ε = 7.5,100 A) 400 1x10-8

300 -10 1x10 MISHFET T T 200 E E -12 F F 1x10 H H IS

100 M Gate current, A -14 MOSHFET Drain current, mA/mm MOSHFET 1x10 0 1x10-16 -14-12-10-8-6-4-20 2 -15 -10 -5 0 Gate voltage, V Gate voltage, V

X. Hu, A. Koudymov, G. Simin, J. Yang, M. Asif Khan, A. Tarakji, M. S. Shur and R. Gaska Appl. Phys. Lett, v.79, p.2832-2834 (2001)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 105 MOSHFET with RF-enhanced Contacts: fmax, Power, PAE

160

150 RF-enhanced

140

130 , GHz 120 Ohmic max f 110

100 0246810

RC, Ω-mm

From: G. Simin and Z-J. Yang, RF-Enhanced Contacts to Wide Bandgap Devices, IEEE EDL V. 28, pp.2 -4 (2007)

LG = 0.2 μm; VD = 30 V

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 106 MISHFET with HfO2

From V. Tokranov, S.L. Rumyantsev, M. S. Shur,

6x10-7 R. Gaska, S. Oktyabrsky, R. Jain, N. Pala, phys. stat. sol. (RRL) 1, No. 5, 199–201 (2007) D -7 1 D2 5x10

4x10-7

10-2

-3 2 Hg 10 -7 3x10 10-4

10-5 2 10-6 C, F/cm -7 -7

2x10 control A/cm |I|, 10

-8 Hf O annealed 10 2 10-9 -7 1x10 650C, 30s 10 -10 -15 -10 -5 0 5 10 as deposited HfO V, V 2 0 -10 -5 0 5 10 15 V, V

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 107 Novel THz Device design: 5-terminal THz GaN HFET

VS1 5 VD1 6

1 5 nm barrier 2DEG 23 4 1 – Ohmic contact (low-T annealed); 2 – Field-control electrode isolation; 3 – Gate dielectric (HFO2) 4 – Source and Drain field-control electrodes /RF-enhanced contacts; 5 – 30 nm Gate 6 – Flash-over suppressing encapsulation From G. Simin, M. Shur, and R. Gaska, presented at LEC-08, U of Delaware, 8/5/08

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 108 Device ADS model: “5-terminal” MOSHFET

Port D RF-enhanced/field control electrodes Num =1 R C R3 C2 R=(Rc0*1e-3/W G) O hm C=0.1 pF

MO SFET_NMO S Var Eqn VAR MO SFET1 VAR 2 Model=MOSFETM1 Rc0=0.2 Length=LGeff Rc0 is the RF-enh contact Port R Width=WG resistance per 1 m m G R4 Num =2 R=1e8 O hm

R C R2 C1 R =(R c0*1e-3/W G ) O hm C=0.1 pF Port S LEVEL3_MO D_Model Var Eqn VAR Num =3 MOSFETM1 VAR 1 NMO S=yes Cgdo=1e-14 Nlev= eps0=8.85e-12 R G = 0.18*W G /LG PMOS=no Cgbo= Gdsnoi=1 q=1.6e-19 m u= 1/q/(NS 0*1e4)/R S HG Vto=VT Cjsw= Theta=0 NS0=1e13 gch=1/RSHG Kp=KP Js= Eta=1e-4 LG=0.03 um VT=-4 Gam m a=0 Tox=TOX Kappa= LGeff=0.03 um CO X=1e4*q*NS0/(-VT) Gam m a2=0 Nss= Kappag= LGS=0.03 um T O X= eps 0*1.5/C O X Zeta= Nfs= Xm u= LGD=0.08 um KP=mu*COX Phi= Tpg=0 Rg=RG WG=15 um Rd=RGD Xj= Rds= RSH0=300 Rs=RGS Ld=0 AllParam s= R C O NT 1 is the c ontac t RSHG=300 resistance per 1 m Cbd= Uo= RCO NTm m =0.3e-4 Cbs= Ucrit= RCONT1=RCONTmm*1e-3 G ate m etal R es is tanc e: Is = Uexp= F or 0.25 um thic k Au gate, RCONT=RCONT1/(WG) for LG=1um and W =1m m Pb= Vm ax=2.7e5 RGS=RSH0*LGS/WG+RCONT RG=100. Cgso=1e-14 Xqc= RGD=RSH0*LGD/WG+RCONT Hence: RG=0.1*W G/LG From G. Simin, M. Shur, and R. Gaska, presented at LEC-08, U of Delaware, 8/5/08

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 109 Novel THz Device design: 5-terminal THz GaN HFET

35 35 HFET HFET 30 5-term 30 5-term 25 MOSHFET 25 MOSHFET 20 20

15 , dB 15 21

10 H 10 MSG/MUG, dB MSG/MUG, 5 5 0 0 -5 -5 10 100 1000 10 100 1000 Frequency, GHz Frequency, GHz

Cut-off frequencies for regular (dash) and 5-terminal (solid) GaN HFETs with 30-nm long gate (ADS simulations).

From G. Simin, M. Shur, and R. Gaska, presented at LEC-08, U of Delaware, 8/5/08

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 110 Terahertz Radiation. Summary.

Technique Power Freq. Tuning Regime Range (THz) Optically > 100 0.3 – Discrete CW/Pulsed pumped THz mW 10 Lines lasers Time Domain 1 μW 0.1 - 2 No Pulsed Spectroscopy

Multipliers μW - 0.1 - 1 10-15% CW mW

Photomixing μW 0.3 -1 Yes CW 0

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 111 THz Generation and Detection

Generation : HEMTs, HBTs - emerging Free electron lasers Quantum cascade lasers Plasma waves – emerging

Molecular lasers (CO2 pump) Graphene THz lasers ? Femtosecond lasers Photomixers Back Wave Tube Frequency multiplication (Gunn/IMPATT/Schottky) Cryogenic detectors NEP ~10-12 –10-14 W/Hz1/2 Bolometers Photodetectors QWIPs Superconducting detectors (SIS, Josephson, bolometers) Room temperature detectors NEP ~10-10 10-12 W/Hz1/2 Pyroelectric detectors Golay cells Schottky diodes Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 112 References

•IMPATT, Gunn Oscillators: –G. I. Haddad, J. R. East, and H. Eisele, International Journal of High Speed Electronics and Systems, vol. 13, pp. 395-427, 2003. • Backward Wave Oscillators: –MicroTech Instruments Inc., “Terahertz Spectrometers, Imaging Systems and Accessories”, Product catalog, Eugene OR, USA, 2007. • Frequency Multipliers: –T. W. Crowe, et al., "Terahertz sources and detectors," Orlando, FL, USA, 2005. • Photomixers: –S. Verghese, et al., Applied Physics Letters, vol. 71, pp. 2743-2745, 1997. –M. Mikulics, et al., Applied Physics Letters, vol. 88, pp. 41118-1, 2006. • Optically Pumped Laser: –Coherent Inc., “SIFIR50, Stabilized Integrated FIR (THz) Laser System”, Datasheet, Santa Clara, CA, USA, 2007. • Quantum Cascade Lasers: –S. Barbieri, et al., Applied Physics Letters, vol. 85, pp. 1674-1676, 2004. –R. Kohler, et al., Applied Physics Letters, vol. 82, pp. 1518-1520, 2003.

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 113 Tutorial Outline

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 114 THz chip Using Ballistic Transport

M. S. Shur and L. F. Eastman (1979)

Ballistic Transistor Has Virtually Unimpeded Current Flow (Dec. 6, 1999) From http://www.bell-labs.com/news/1999/december/6/1.html

Intel plans Itanium 'leapfrog' to 32-nm Colleen Taylor, Contributing Editor -- Electronic News, 6/14/2007

If the 25 nm node predicted by ITRS is reached in 2009, all transistors will be ballistic

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 115 All Transistors will be Ballistic in 2009

International Technology Roadmap for Semiconductors projections for minimum physical gate length. (Data from http://www.itrs.net/Common/2004[ Update/2004_00_Overview.pdf) 50 45 40

)

m 35

( 30

t 25

n 20

t 10

a 5

G 0 2005 2006 2007 2008 2009 Year Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 116 Waves of electron density (Plasma Waves)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 117 THz Generation and Detection by 2D Plasma Waves

2 4 π e nd ω = sk , s = , kd <<1 m ε

Instability: Dyakonov Shur PRL (1993) Detection: Dyakonov Shur IEEE EDS (1996)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 118 Plasma Wave Electronics

Hokusai Print

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 119 Dispersion of Plasma Waves

3D 2D ungated 2D gated - + r - r d + E - + - + E + r E

2 2 ω 2 N N e 3D e 2 D e N2Dd ωp = ω p = k p = k kd<<1 εε0m 2 0 m εε 0m ωp ωp εε ωp

k k k

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 120 Plasma Wave Instability in Ballistic FET

Boundary conditions The source and drain are connected to a current 1.5 source and the gate and source are connected to 1 a voltage source, Ugs. 0.5 This corresponds to the constant value of U = 0

Uo at the source (x = 0) and to the constant value -0.5 of the current at the drain (x = L).

Dimensionless Increment -1 s2 −v2 s2−v2 s+v -1.5 o ω''= o ln o -1.5 -1 -0.5 0 0.5 1 1.5 v /s ω' = πn s−v o 2Ls 2Ls o s = (eUo/m)1/2 where n is an odd integer for |vo| < s and an even integer for |vo| > s.

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 121 Demonstrated Plasma Wave Phenomena

•Resonant detector J. Lu and M. Shur (1998) W. Knap et al (2002)

•Emission Deng et al (2004) W. Knap et al (2004) •Photomixer

V. Ryzhii et al (2002) Otsuji et al (2003)

•Mixer M. Lee et al (2005)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 122 Plasma Electronics Advantages

•Small size (easy to fabricate matrixes/arrays)

•Compatible with VLSI technology

•For detectors: –High sensitivity –Broad spectral range –Band selectivity and tunability –Fast temporal response

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 123 2D Plasmonic Devices for THz Applications

THzTHz DetectorsDetectors THzTHz GeneratorsGenerators andand MixersMixers

M. Dyakonov and M. Shur, IEEE M. Dyakonov, M. Shur, PRL (1993) T-ED (1996) K. Hirakawa, APL (1995) K. Guven et al., PRB (1997) K. D. Maranowski, APL (1996) V. Ryzhii et al., JAP (2002) V.V. Popov et al., Physica A (1997) W. Knap et al., APL, JAP S.A. Mikhailov, PRB (1998); APL (1998) (2002) P.Bakshi et al., APL (1999) X.G. Peralta et al., APL (2002) N. Sekine at al., APL (1999) A. Satou et al., SST (2003) R. Bratshitsch et al., APL (2000) V.V. Popov et al., JAP (2003) Y. Deng at al., APL (2004) V. Ryzhii et al., JAP (2003) W. Knap et al., APL (2004) F. Teppe et al., APL (2005) M. Dyakonov and M.S.Shur, APL (2005) I.V. Kukushkin et al., APL N. Dyakonova et al., APL (2006) (2005) Otsuji APL (2006) DRC 2007 D. Veksler et al., PRB (2006)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 124 Semiconductors Competing for THz Applications

) GaAs GaN

H 10

(

y 5 Plasma modes

e Si

q 1

e r Transit mode F 0.5

0.02 0.05 0.1 0.2 0.5 1 Gate Length (micron) From V. Ryzhii and M.S. Shur, Plasma Wave Electronics Devices, ISDRS Digest, WP7-07-10, pp 200-201, Washington DC (2003)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 125 Channel with 2DEG as detection medium

FETs Diodes Vertical diode: THz L

Source Drain Gate

L 2D Channel channelLateral diode: δU~P W AlGaN GaN

ddep Gated Ungated d 2D 2D

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 126 THz Generation in Nanometer-Gate HEMT via Gated-Ungated Plasmon Interaction

Knap W. et al, APL (2004) THz radiation IEEE Spectrum (May 2004) 3.0

300 2.5 Ungated plasmons 2.0 ω 200 p 1.5 (1/THz) 0

1.0 1/f Gated plasmons 100 InSb Detector Signal (mV) 0.5

k 0 0.0 0.00 0.2 0.4 0.6 0.8 π/(2 W) π/(Lsd) Usd (V) 60-nm The most efficient THz generation gate occurs when BOTH the ungated and gated plasmons are in resonance

InGaAs 60-nm-wide gate HEMT (Courtesy of W. Knap) Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 127 Achieved Detector Performance

GaAs : 1 THz detection demonstrated R ~ 10 - 103 V/W n = 2×1011 cm-2 L = 0.2 µm. Detection 120 GHz - 2.5 THz GaN : 1 THz detection demonstrated n = 2 ×1013 cm-2 & L =2 µm Room temperature generation (Knap et al Veksler et al (2006) Si : 120 GHz – 3 THz detection demonstrated NEP ~ 10-10 W/Hz

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 128 Experimental 200 and 600 GHz setups in our lab

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 129 HEMT for Resonant THz detection

1) 2) Theory: 3.0 Experiment: d 2.5 f=0.761 THz 2.0 AlGaN/GaN

V, arb. units 1.5 Δ 4 K 1.0 20 K 0.5 70 K 0.0 Response Response -5 -4 -3 -2 -1 0

) 3

ω 4π end2 = 2 k 2 1 p εm 1) M. Dyakonov and M. S. Shur, Phys. Rev. Lett. 71, 2465 (1993) 2) A. El Fatimy, N. Dyakonova, F. Teppe, W. Knap, N. Pala, R. Gaska, Q. 0 Fareed, X. Hu, D. B. Veksler, S. Rumyantsev, M. S. Shur, D. Seliuta, G. frequencyplasma (THz -5 -4 -3 -2 -1 0 Valusis, S. Bollaert, A. Shchepetov, Y. Roelens, C. Gaquiere, D. Theron, and A. Cappy, Electronics letters, Vol. 42 No. 23, 9 November (2006) gate voltage (V)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 130 Non-resonant detection (ωτ<<1)

30 f = 0.2 THz; T=300 K Ugs=-100 mV 250 nm GaAs FET 25 25 Ugs=-200 mV U = 0 mV gs 20 Ugs=-300 mV 20 Ugs = -100 mV , mA

d 15 Ugs=-350 mV 15 U = -200 mV gs 10 10 U = -300 mV gs 5 Response (Arb. Units) 5 U = -400 mV gs Drain current I 0 0 10-4 10-3 10-2 012 Drain Current I (A) Drain voltage U , V d ds U 2 Symbols – experiment V = a Colored curves - theory response 1/2 jjdsat<< 4(UUgs−− th )(1 jj d / sat ) D. Veksler et al , Phys. Rev. B 73, 125328 (2006).

131 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 131 Resonant detection near instability threshold

0.15 I =8mA I =22mA d d

0.10

f = 0.6 THz; T=300 K GaAs FET 250 nm U, mV δ 0.05

ω τ <1, but ω τ >>1 0.00 0 0 eff -0.3 -0.2 -0.1 0.0 0.1 Instability increment Gate voltage V , V gs 11=−vd 22ττeff ( L ) The decrement decreases with electron velocity or drain current due to approaching to the threshold of the plasma wave instability.

F. Teppe, W. Knap, D. Veksler, et al, Appl. Phys. Lett. 87, 052107 (2005)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 132 Homodyne detection by plasma FET: Mixing of laser modes Heterodyne detection has a much higher

sensitivity and is usable for diffuse0.1 reflection imaging 0.0 a) 2.52 THz -0.1 THz laser -0.2 Chopper -0.3 S I F IR - 5 0 F P L ( 1 T H z – 7 TH z ) Oscilloscope -0.4 Single mode regime Lens -0.5 0.1 0.0 Response, mV Response, b) Mode mixing 0.1 -0.1 -0.2 0.0 1 -0.3 Response, mV Response, -0.1 -0.4 10.00 20.00 30.00 Time, μs -0.5 0123456789 Spectrum of laser mode beatings

Amplitude (a.Amplitude u.) Time, ms 0 From Dmitry Veksler, Andrey Muravjov, William Stillman, Nezih 01234Pala, and Michael Shur, Detection and Homodyne Mixing of Frequency (MHz) Terahertz Gas Laser Radiation by Submicron GaAs/AlGaAs FETs, in Abstracts of IEEE sensors Conference, Atlanta, GA, October 2007 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 133 Comparison of THz Detection Devices (300 K)

Si MOS Response

NEP -10 Detector time 10-7 10 /Hz (W/Hz½) 2 (Hz) 10-12

-14 Not tunable 10 -11 -12 -8 -16 Microbolometer 10 –10 1μs 10 10 0.5 Spectral density, V density, Spectral 10-18 50 60 70 80 90 Not tunable Frequency f, Hz -7 -9 Pyroelectric 10 -10 1 ms -9 L =120nm 10 g NEP, W/Hz 200nm 300nm Schottky Diode 10-9 –10Not-11 tunable< 10 ps

10-10 0.0 0.2 0.4 0.6 0.8 Plasma Wave -6 -10 10 –10 < 10 ps ? Gate voltage V , V Detector Tunable g Advantages of Plasma wave detector: El Fatimy, N. Dyakonova, F. Teppe, W. •Band selectivity and tunability (resonant detection) Knap,D. B. Veksler, S. Rumyantsev, M. •Fast temporal response S. Shur, N. Pala, R. Gaska, Q. Fareed, X. Hu, D. Seliuta, G. Valusis, C. Gaquiere, D. •Small size (easy to fabricate matrixes/arrays) Theron, and A. Cappy, IElec. Lett. (2006). •Compatible with VLSI technology Table courtesy of D. Veksler, RPI •Broad spectral range Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 134 Schottky barrier (SB) + Plasma waves

Conventional diode Heterodimensional diode Metal 3D contact 2DEG

Depletion Semiconductor Depletion Heterodimensional diodes vs. conventional diodes Smaller series resistance Smaller capacitance Hence, a higher operating frequency is expected 2d Plasma in series with the SB

W.C.B. Peatman, T.W. Crowe, and M. Shur, "A Novel Schottky/2-DEG Diode for Millimeter and Submillimeter Wave Multiplier Applications," IEEE Electron Device Lett., 13, 11 (1992)

135 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 135 Responsivity vs. radiation frequency (zero bias)

Orthogonal polarizations:

-1 Theory ■ Eω || Channel 10 ■ Eω ⊥ Channel -2 0123 10 f, THz -3

(arb. units.) 10 10-3

10-4 10-4 10-5 Response (a.u.) Responsivity

0.00.51.01.52.02.53.0 1.0 1.5 f (THz) f (THz)

D. Veksler, et al. Proc. 5th IEEE Conference on Sensors, p 323 (2006)

136 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 136 Coupling of THz radiation into transistor. Experiment

Lock-in

Chopper SR8300 λ=184 μm

FIR Laser

Polarizer Vgs

The spatial images are obtained by Rload recording radiation induced drain- Vds to-source voltage as a function of the transistor position with respect Displacement 5÷10 μm to the focused THz beam 3d NanoMax 341

Veksler, D.B. Muraviev, A.V. Elkhatib, T.A. Salama, K.N. Shur, M.S. , Plasma wave FET for sub-wavelength THz imaging, International Semiconductor Device Research Symposium December 12-14, 2007 College Park, Maryland, USA 137 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 137 Transistor responsivity pattern exhibits two spots of138 maximum response with different signs Source: Terahertz gas laser SIFIR- Beam profile in 50 at 1.63 THz (184 μm)

1.00

I n 0.75 t e n 1000 the focal spot: s it 0.50 δU , V y

( a . u 0.25 800 d . ) 0.00 0 400 600 200 ) m μ ( 400 400 Y -2.9E-5 X 600 (μm ) 800 200 300 -2.4E-5 Vgs = 0.45V,D jd = 0 200 -1.9E-5 -1.5E-5 100 -9.7E-6 0 -4.8E-6

G m 0 μ -100 4.8E-6 Y, S -200 9.7E-6 1.5E-5 -300 1.9E-5 -400 2.4E-5 Fujitsu FHX06X 2.9E-5 -500 GaAs/AlGaAs HEMT -400 -300 -200 -100 0 100 200 300 400

Lg=0.25μm X, μm W=200μm Veksler, D.B. Muraviev, A.V. Elkhatib, T.A. Salama, K.N. Shur, M.S. , Plasma wave FET for sub-wavelength THz imaging, International Semiconductor Device Research Symposium December 12-14, 2007 College Park, Maryland, USA

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 138 Theory

Hydrodynamic equations for 2D gas in the FET channel: Z Z ∂∂vvveU ∂ gs gd

+++=v 0 ~

~ U ∂∂txτ mx ∂ Ua b ∂∂nnv() ω +=0 ∂∂tx ω Boundary conditions: en= CU ω

U (0) − j (0)Z = U a , U (L) + jω (L)Z = U b . We see that the response might have different signs δ 2 2 depending on the ratio |Ua | /|Ub | ω −1/3 * −2/3 3 0 = (μU g ) (CL ) 1 ⎛ω ⎞ ⎛ |U |2 |U |2 ⎞ V = − ⎜ 0 ⎟ ⎜ a − b ⎟ * ⎜ 1/ 2 3/ 2 ⎟ Z ≈ −iωL 4U gs −Uth ⎝ ω ⎠ ⎝ ()1− jd / jsat ()1− jd / jsat ⎠

Veksler, D.B. Muraviev, A.V. Elkhatib, T.A. Salama, K.N. Shur, M.S. , Plasma wave FET for sub-wavelength THz imaging, International Semiconductor Device Research Symposium December 12-14, 2007 College Park, Maryland, USA 139 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 139 Transistor THz responsivity vs. drain current and gate voltage Theory: Experiment:

1/2 3/2 Response=1/(1-I /I ) -α/(1-I /I ) Vgs=-0.63 V d sat d sat 2 Vgs=-0.45 V α=0, I =5e-2 sat Vgs=-0.30 V α=0.2, I =1e-2 sat α=0.7, I =5e-3 Vgs=-0.15 V sat 0.6 Vgs= 0.0 V

0.0 , mV

0 d U δ

Response, a.u. -0.6

110j , ma 110 d j , ma Veksler, D.B. Muraviev, A.V. Elkhatib, T.A. Salama, K.N. Shur, M.S. , Plasma wave FET for sub-wavelength THz imagid ng, International Semiconductor Device Research Symposium December 12-14, 2007 College Park, Maryland, USA 140 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 140 THz Imaging with plasma FET

•THz image is a result of superposition of the responses from different parts of the transistor.

•Drain current leads to increase in = + the ratio between negative and positive responses. As a result the maximum of the response shifts in XY plane.

Sub-wavelength THz resolution is typically reached using a needle or sub- wavelength diaphragms and optically induced diaphragms Here sub-wavelength resolution might be achieved due to variation of the responsivities driving the transistor with the drain current

Veksler, D.B. Muraviev, A.V. Elkhatib, T.A. Salama, K.N. Shur, M.S. , Plasma wave FET for sub-wavelength THz imaging, International Semiconductor Device Research Symposium December 12-14, 2007 College Park, Maryland, USA 141 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 141 Sub wavelength shift of sensitivity maximum

Driving transistor toward saturation regime we change

ratio betweenI I I= = =5mA, 5mA, 5mA, V V positiveV=-0.3=-0.15=0 V V V and negative responses d dd gsgs gs I = 5mA, V =-0.4 V d gs 200 500500 180 500 160 400400 140 400 120 300300 m) m) m) m)

μ μ μ μ 100

Y ( Y (

Y ( 300 m)

μ 80 200200 Y ( 60 200 Shift ( 40 100100 20 100

00 0 00 100 100 200 200 300 300 400 400 500 500 -0.4 -0.3 -0.2 -0.1 0.0 0 XX ((μμm)m) 0 100 200 300 400 500 V (V) gs X (μm)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 142 Shift of the response maximum position vs. length

of a high field region in the channel, ΔLg.

•Plasmonic responsivity 200 mechanism works as a m) 180 μ magnifying glass: ~180 μm 160 140 shift from nanometer scale 120 change in the electric field 100 distribution along the channel 80 60 •This dependence could be 40 used as a calibration curve for 20 Response peak shift ( Response peak 0 determining the positions of the 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 peak response as function of Δ L (nm) bias of FETs of different design g

Vd and Vs are radiation induced AC voltages at source and drain sides of the channel Zgd Zgs

~ At Id=0 sign of the signal

Vs ~ Vd depends on which AC source is stronger : Vd or Vs

At Id>0 response signal caused by Vs increases while signal caused by Vs decreases accordingly 2 Ua δU0 = 1/2 4(UUgs−− th )(1 jj d / sat ) Veksler, D.B. Muraviev, A.V. Elkhatib, T.A. Salama, K.N. Shur, M.S. , Plasma wave FET for sub-wavelength THz imaging, International Semiconductor Device Research Symposium December 12-14, 2007 College Park, Maryland, USA Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 144 Tutorial Outline

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 145 Polarization induced 2D electrons and holes in pyroelectric semiconductors

From A. Bykhovski, B. Gelmont, M. S. Shur J. App. Phys. Vol. 74 (11), p. 6734-6739 (1993)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 146 THz Experiments in Progress

f (THz) 3 6 9 121518212427

1.0

0.8

0.6 Transmission CdS with AlN/ CdS

0.4 Transmission

0.2 AlN phonon

0.0 100 200 300 400 500 600 700 800 900 wave numbers (cm-1)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 147 Responsivities of CNT terahertz detectors

From Fu et al. Appl. Phys. Lett. 92, 033105 2008

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 148 Semiconductor Grains Forming Plasmonic Crystal

Semiconductor •3D granular media, with semiconductor grains inserted grains in pyroelectric matrix can serve as uniaxial crystal operating in THz range of frequencies. P o •The properties of this crystal can be easily tuned by external magnetic and electric Pyroelectric fields and by optical Matrix excitation.

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 149 Field Distribution at resonances

From T. V. Teperik, F. J. Garcia de Abajo, V. V. Popov, and M. S. Shur, Strong terahertz absorption bands in a scaled plasmonic crystal, Appl. Phys. Lett. 90, 251910 (2007)

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 150 THz Array for Femtosecond Laser Excitation

From . V.V. Popov, G.M. Tsymbalov, D.V. Fateev, M.S. Shur., Applied Physics Letters, 2006, Vol.89, No.12, P.123504/3 0.30

0.25

0.20

0.15

0.10

0.05

0.00 0.00 2.50 5.00 7.50 10.00 12.50 15.00

October 14, 2004 Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 151 New physics of Movable Quantum Dots

•Self-assembled quantum dot arrays •Coulomb blockade •Light concentration in quantum dots •Left handed materials (NIM)

New Potential Applications •Terahertz detectors •Terahertz emitters •Terahertz mixers •Photonic terahertz devices •Photonic crystals •Plasmonic crystals •Solar cells and thermovoltaic cells

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 152 HEMT Structure with Common Channel and Large Area Grating-Gate

Grating Gate

From N. Pala, D. Veksler, A. Muravjov, W. Stillman, R. Gaska, and M. S. Shur, Resonant Detection and Modulation of Terahertz Radiation by 2DEG Plasmons in GaN Grating-Gate Structures, in Absracs of IEEE Sensors Conference, Atlanta, GA, October 2007

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 153 Measured Transmission Spectrum of

Grating-gate FETs 1.4 L=4 μm w=1μm 1.2 1.0 0.8

0.6 0.4

Transmission (a.Transmission u.) 0.2 2 e N 0.0 2D 12345678 ω p = k Frequency (THz) 2 0m εε Correct frequency ratio

From N. Pala, D. Veksler, A. Muravjov, W. Stillman, R. Gaska, and M. S. Shur, Resonant Detection and Modulation of Terahertz Radiation by 2DEG Plasmons in GaN Grating-Gate Structures, in Abstracts of IEEE Sensors Conference, Atlanta, GA, October 2007

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 154 THz signal (a) transmitted through grating gate biased by a pulsed signal (b)

0 -2

-4 -6 (b)

Gate Pulse (V) Pulse Gate -8 2 1 0

-1 (a) -2 -30 -20 -10 0 10 20 Time (ms) Transmited Signal (mV) Signal Transmited

From N. Pala, D. Veksler, A. Muravjov, W. Stillman, R. Gaska, and M. S. Shur, Resonant Detection and Modulation of Terahertz Radiation by 2DEG Plasmons in GaN Grating-Gate Structures, in Abstracts of IEEE Sensors Conference, Atlanta, GA, October 2007

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 155 Conclusions

•Applications of THz technology are exploding •Terahertz photonics: established technology but expensive and bulky •Terahertz electronics: low powers, Schottky diode technology is mainstream, transistor technology is emerging •Plasma wave electronics: resonant and non resonant detection in a wide temperature range in different materials systems; nanowatt sources with milliwatt potential •Grainy multifunctional pyroelectric materials are predicted to form a new THz medium

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 156 To probe further

Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 157 Hard Work But Steady Progress!

Photo by Igor Stolichnov (2005) used with permission Michael Shur ([email protected]) http://nina.ecse.rpi.edu/shur 158