Nanowires: a Platform for Nanoscience & Nanotechnology

Nanowires: A Platform for Nanoscience & Nanotechnology

Charles M. Lieber Harvard University

http://cmliris.harvard.edu Lieber Research Group

Brian Timko Quan Qing Hao Yan Ping Xie Bozhi Tian Yongjie Hu Jian-Ru Gong Thomas Kempa Guihua Yu Tzahi Cohen-Karni Hwan Sung Choe Yajie Dong Lu Wang Sirui Zou Xiaocheng Jiang Didier Cassanova Yizhe Zhang Quihua Xiong

Ritesh Agarwal Xiaolin Zheng Wei Lu Ying Fang Ali Javey Xuan Gao Fernando Patolsky Yat Li Silvija Gradecak Hong-Gyu Park Alex Wong Won-Il Park Pavle Radovanovic Jie Xiang Chen Yang Mike McAlpine Yue Wu Outline of Presentation

Nanowire Platform Functional Nanowire Devices Nanoelectronic-Biology Interface Conclusions Nanowires as a Platform

Synthetic control of structure and composition on many length scales Predictable and tunable electronic properties allow fundamental limits of nanodevices/1- dimensional systems to be addressed Nanowires with controlled chemical and electronic properties represent an ideal building block for exploring new functional devices and hybrid materials. Nanoscale wires/nanowires are of central importance to integrated nanosystems

Exploit to answer what is possible! History: Key Growth Concepts

Si/Au phase diagram

AuSi(ls) AuSi(ls) + Si(s)

rmin = 2σLVVL /RTlnσ ~ 100 nm

σLV is liquid-vapor interfacial free energy

VL is the liquid molar volume σ is the vapor phase supersaturation Wagner & Ellis, Appl. Phys. Lett. 4, 89 (1964) Wagner, Whisker Technology, (Wiley, New York 1970) p. 47 Nanowires: A General & Predictable Approach

Breaking symmetry for 1D growth. Nanoscale wires can be prepared rationally by exploiting a catalyst to direct preferentially the addition of reactant.

The key issue for controlled nanowire growth is the reactor hot zone generation of nanometer scale ‘catalyst’ clusters. supersaturation/nucleation The growth process begins when the catalyst becomes growth supersaturated with reactant, and termination terminates when the nanowires pass out of the hot reaction zone.

Morales & Lieber, Science 279, 208 (1998) Hu, Odom & Lieber, Acc. Chem. Res. 32, 435 (1999) Nanowires: A General & Predictable Approach

Breaking symmetry for 1D growth. Nanoscale wires can be prepared rationally by exploiting a catalyst to direct preferentially the addition of reactant.

Morales & Lieber, Science 279, 208 (1998) Hu, Odom & Lieber, Acc. Chem. Res. 32, 435 (1999) Nanocluster-Catalyzed Nanowire Growth: An Early Summary

Material Group IV Group IV III-V III-V Alloys II-VI Alloys:

Si SixGe1-x GaAs GaAsxP1-x ZnS

Ge GaP InAsxP1-x ZnSe GaN CdS InAs CdSe InP Growth 330-1200 850-950 700-1000 800-950 700-1000 Conditions Fe, Ni, Au Fe, Au Cu, Ag, Au Au, Ag Au

Composition pure 1:1 defined by 1:1 starting composition

minimum diameters ~3 nm with single crystal structures controlled nucleation yields monodisperse diameters with controlled lengths surface properties tailed for assembly and device properties

Duan & Lieber, Adv. Mat. 12, 298 (2000) How Perfect are Nanowires? Low-temperature transport provides measure of ‘impurity and defect-free’ length scale.

dI/dVsd I

Vsd Vg S D dI/dVsd Vgate sd V Vsd

Constraints for observing quantized charge transport: Vg 2 1. Charging energy U=e /C > kBT 2 2 2. ΔEΔt = (e C)()RtC > h Rt >> h e (≈ 26kΩ) Single Electron Tunneling in Silicon Nanowires

T = 4.2 K L = 400 nm

Tilke, etc. JAP, 89, 8159, 2001

Regular period for coulomb charging peaks consistent with single charge tunneling through one quantum structure with discrete energy levels. Transport through single quantum structures is observed for nanowire lengths up to at least 400 nm, ca. 10x longer than in any nanofabricated silicon. Impurities or defects that perturb electronic transport must be separated on length scale >400 nm! Zhong, Fang, Lu & Lieber, Nano Lett.5, 1143 (2005) Nanowire Heterostructures & Superlattices

1-d growth nucleation

axial growth

radial growth axial heterojunction/superlattice

radial heterostructures

Gudiksen, Lauhon, Wang, Smith & Lieber, Nature 415, 617 (2002) Lauhon, Gudiksen, Wang & Lieber, Nature 420, 57 (2002) Germanium/Silicon Core/Shell Nanostructures

5nm

Core/shell nanowire structure enables Control of surface defects and states Design of carrier gases confined in uniform 1D potential Reduced scattering and correspondingly achieve higher mobility transistors as well as enable new studies of quantum phenomena at low-temperatures!

Lu, Xiang, Timko, Wu & Lieber, PNAS 102, 10046 (2005) Pushing Nanowire Transistor Limits

Transconductance = 26 μS/V Transconductance = 60 μS/V

Max Ion= 35 μA Max Ion= 91 μA. Scaled values (Vdd=1V; 70/30 on/off): Scaled values (Vdd=1V; 70/30 on/off): Gm = 1.4 mS/μm Gm = 3.3 mS/μm Ion = 0.78 mA/μm Ion = 2.1 mA/μm First demonstration that a nanowire transistor could exceed limits of top-down devices!

Xiang, Lu, & Lieber, Nature 441, 489 (2006) Nanowire FETs: How Good Are They?

TransconductanceL= 40 nm, 8x= faster182 μS/V than Si p-MOSFET, and shows Max I = 152 μA fundamentalon limit > 2 THz Scaled values (Vdd=0.5V; 70/30 on/off): G = 5.0 mS/μm Ion mis ~100% of the ballistic limit at low bias Ion = 1.7 mA/μm S = 160 mV/decade Hu, Lieber & coworkers, Nano Lett. 8, 925 (2008) Xiang, Lu, & Lieber, Nature 441, 489 (2006) Double Quantum Dot with Integrated Charge Sensor Based on Ge/Si Nanowires

T = 100 mK

Fully control of interdot coupling and barrier height by local top gates Plunger gates control charge number Double dot capacitively coupled to sensor dot on adjacent nanowire Charge sensing critical for single-electron double dots and spin control Hu, Churchill, Lieber & Marcus, Nature Nano. 2, 622-625 (2007) Integrated Charge Sensors and Fast Manipulation

honeycomb (no pulses):

Ic0c1_1381 60 bias=-0.2 mV no RF pulses 55 0 current (10 current -10 -20 (mV)

R 50

NW V -30

-40 -12 A) 45 -50 -60

40 380 385 390 395 400 VL (mV) RF in square wave on VL and VR

Ic0c1_1380 60 bias=-0.2 mV • scaled dot size defined by lithography 10 MHz 55 current (10 current • two charge sensors on same -5 -10 nanowire allows readout of double dot (mV)

R 50

V -15 charge state -20 -12 A) • two RF gates allow fast (~1ns) 45 -25 -30 manipulation of double dot 40 380 385 390 395 400 VL (mV) Core/Shell Architecture & Photovoltaics: What is possible and what can we learn?

p-type/intrinsic/n-type (p-i-n) core/shell/shell silicon nanowires in which the structure and composition of the core and shells are readily controlled. Radial structures might enable improved carrier collection and overall efficiency, comparable to single crystal semiconductors, while retaining solution processing of nanoparticle and organic systems.

Tian, Zheng, Kempa, Lieber & coworkers: Nature 449, 885 (2007) p-i-n Core/Shell Nanowire Properties

Dark current-voltage (I-V) data demonstrate (i) ohmic contacts and (ii) good rectifying/diode behavior with quality factors, n, of ~2. Under 1-sun illumination, yield an open circuit voltage of 0.260 V, a short circuit current (density) of 0.503 nA (24 mA/cm2), and stable operation of at least 8-months! 1-sun efficiency, ~3.5%, and current density exceed values achieved with nanoparticle & nanorod composite systems, although open circuit voltage is lower. Power output is ~ 1 nW (ca. 100 W/m2)

Tian, Zheng, Kempa, Lieber & coworkers: Nature 449, 885 (2007) Axial & Coaxial p-i-n Nanowire Platforms for Photovoltaics

Optical absorption and transport characteristics are unique compared to radial core/shell nanowires. Important point of comparison for studies of carrier generation, recombination and collection at the nanometer scale. Axial p-i-n Nanowires: Synthesis & Properties

Controlled modulation of p-, i-, and n-type diode regions Etching delineates different doped Si regions

Good quality diodes (not Schottky) with quality factors for i = 4um of 1.2-1.3.

∆Isc is proportional to ∆ilength implies that photocurrent is predominantly from i-region

Kempa, Tian, Lieber & coworkers, Nano Lett. 8, 3456 (2008) Exploring Novel Nanostructure To Push Limits of Photovoltaic Efficiency

I. Tandem Solar Cells Controlled synthesis enables integration of ≥2 p-i-n diodes in series with independent control of junctions. Substantial increase in open circuit voltage realized in ‘tandem’ axial single nanowire photovoltaic elements!

Kempa, Tian, Lieber & coworkers, Nano Lett. 8, 3456 (2008)

II. MQW Solar Cells

Qian, Lieber & coworkers, Nature Mater. 7, 701 (2008) Assembly of Multi-Functional Structures: NW- Photovoltaic Powered Nanodevices

Individual coaxial nanowires function as robust photovoltaic devices with sufficient power output to drive nanoelectronic devices ‘on chip’. A single photovoltaic nanowire integrated with a nanowire sensors is capable of powering the nanowire sensor device without external input.

Tian, Zheng, Kempa, Lieber & coworkers: Nature 449, 885 (2007) Interfaces between nanoelectronic & biological systems

Natural length-scale Create new tools for for electronic interfaces biophysics to healthcare

Nanoelectronic-Biological Systems

Hybrid materials that enable new opportunities in science & technology Nanoelectronic – Biology Interface

Requirements: Nanoscale devices – the right size (stuff) Reproducible and tunable electronic properties Controlled and predictable bio-surface properties Unconventional fabrication to enable flexible and transparent substrates and/or 3D structures

⇒⇒ Nanowires Nanowire Nanosensors: Beginning

A nanotransistor is transformed into a nanosensor by modifying the surface with a receptor. Changes in the surface charge ‘gate’ the device and yield a conductance change.

Detection of Proteins

+ streptavidin(25 pM)

Real-time label-free buffer High-sensitivity and specificity

Cui, Wei, Park & Lieber, Science 293,1289 (2001) Nanosensor Chip for Real-Time, Label-Free Multiplexed Detection

Bottom-up/top-down hybrid fabrication yields large number of addressable nanowire elements Assemble distinct types of nanowires on single chip Personalize sensor elements with distinct receptors

Cui, Wei, Park & Lieber: Science 293,1289 (2001) Patolsky, Zheng, Lieber et al., PNAS 101, 14017 (2004) Patolsky, Zheng & Lieber, Nature Protocols 1, 1711 (2006) Multiplexed Cancer Marker Detection

Buffer

2200 a Multiplexed, real-time 1.4 pg/ml PSA 2100 monitoring of cancer b marker proteins. 2000 c Quantitative & selective 2 pg/ml CEA 1900 d detection of protein 1800 concentration to e MUC femtomolar level. 1700 f General platform for 1600 multiplexed, ultrasensitive, 1500 0 2000 4000 6000 8000 real-time detection of proteins and other species! Time / s

Zheng, Patolsky & Lieber, Nat. Biotech. 23, 1294 (2005) Undiluted Blood Serum Analysis

Serum samples are characterized after single step ‘desalting’ purification. (1) buffer; (2) Donkey Serum (DS), 59 mg/ml total protein; (3) DS + 2.5 pM PSA; (4) DS + 25 pM PSA

(1) DS + 0.9 pg/ml; (2) DS

Marker proteins are detected selectively in presence of ca. 100-billion-fold excess of serum proteins!

Zheng, Patolsky & Lieber, Nat. Biotech. 23, 1294 (2005) Making Good on the Promise: Commercialization

• Vista combines nanowire devices and biotechnology to provide all the tools needed to measure biomarkers over time. • Revolutionize monitoring of biomarkers of therapeutic response and toxicity in the clinic and lab for drug development through patient care.

Vista Therapeutics, Inc. www.vistatherapeutics.org Ultimate Sensor: Single-Particle Detection

Can nanoscience enable detection at ultimate limit of a single biological entity?

Patolsky, Zheng, Lieber et al., PNAS 101, 14017 (2004) Single-Particle Detection: How Small?

Can the sensitivity of nanowire sensors be pushed to enable true single molecule detection? Consider the case of small oligonucleotides:

Fang, Zheng, Tian, Yan, Zhou & Lieber Nanoelectronic-Cell/Tissue Interfaces

An example:

Neurons + Nanosensors

Nanowire nanoelectronic devices can enable: Interface to cells at natural scale of biological communication Input/output of electrical signals Input/output of chemical/biological signals Nanowire/Neuron Junctions IC Stimulation NW1 Stimulation NW1 NW2 axon

NW3 NW4

Nanowire (NW) response correlated w/conventional measurements Multiplexed recording with flexible arrays is straight forward Nanowire/neuron junctions can be localized at level of individual neurites

Patolsky, Timko, Lieber & coworkers, Science 313, 1100 (2006) Nondestructive, Real-time Neurotransmitter Detection

Selective detection of neurotransmitter dopamine to at least 100 fM sensitivity Reversible & nondestructive Potential for high spatial and temporal resolution Potential for simultaneous neurotransmitter & action potential recording

X. Jiang, L. Wang, S. Zou & Lieber General Approaches for Building & Using Nanoelectronic Tools? Nanowire-Heart Interfaces: Pushing the Limits

Flexible and transparent chips enable simultaneous electrical recording and optical imaging in 3D configurations not accessible with traditional planar technologies! Enables electrical recording with simultaneous optical registration down to cellular level with opaque tissue/organ samples Starting point for implants, “smart” engineered tissue, and functional biomaterials. Timko, Cohen-Karni, Yu & Lieber Interfacing to Brain Slices

S. Pal & V. Murthy Q. Qing, B. Tian, & Lieber Vision for Life Sciences Nanoelectronic-Biological Interfaces Enable: Diagnostic devices for disease detection General detection & kinetics platform Nanoelectronic-Biological New tool for single-molecule Interfaces detection/biophysics Powerful devices for electronic and chem/bio recording from cells, tissue & organs Potential implants for highly functional & powerful prosthetics, as well as hybrid biomaterials enabling new opportunities Conclusions 9 Synthetic control of nanowire structure and composition demonstrated at level beyond other nanomaterials. 9 Nanowire structural and compositional diversity exploited to push limits of conventional and quantum electronic devices, as well as to explore new device concepts, such as for solar energy conversion. 9 Nanowire nanoelectronic devices demonstrated as broad tools for life sciences, from ultrasensitive detection to electrically-sensitive recording from cells and tissue with potential for novel interfaces for prosthetics.