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R&D of IR Detectors and Emitters

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R&D of IR Detectors and Emitters Soreq nanodots and nanocrystals for infrared photodetectors Yossi Paltiel Solid State Physics Group Soreq NRC III-V compounds Most of our work Are bulk devices for MWIR Quantum detectors SWIR- Nano-crystals MWIR- Nanodots LWIR-Quantum wells THz Quantum wells Bulk problems and possible solution • Low temperature operation • Wide band wavelength response • Restricted flexibility in choosing the peak wavelength Nano Why Nano and Meso? Call for Research Proposals in Advanced Materials and Nanotechnology, Israel- Ukraine Cooperation Impressive A lot of money Using Quantum effects in the world of high temperatures (300K) Nanodots in lasers and detectors Light prorogation E H ¾ Theoretically, high temperature operations. 1D QW energy shift as a function of L 105 InSb ¾ Long lifetime 104 dE 1000 ¾ Normal light absorption 100 10 ¾ Narrow absorption lines 1 0 5 10 15 20 25 30 35 40 ¾ Changing dots size will change the blue shift and could give L [nm] multispectral detection Nano crystals for shorter wavelength Uri Banin room T precursors In/GaCl3 and P/As(SiMe3)3 P = P O liquid surfactant, stirring and at o InCl3+As(SiMe3)3 InAs + 3Me3SiCl “high T,” 250-300 C Wavelength (nm) Quantum confinement in 1600 1200 800 600 InAs nanocrystals 2.4 nm Optical spectra 2.9 nm ) . u . a ( 3.3 nm ) . y u . a nsit Quantum Dot e 4.0 nm t n ance ( E 4.6 nm b 1Pe Absor inescence I 1Se 5.0 nm Eg Lum 5.8 nm 1Sh 6.4 nm 1Ph r 1.01.52.02.5 Energy (eV) Transport and dissipation The molecules used 1.4 InAs - NPs AA112C4S2 AAC1325S3 1.2 1334 1466 1.0 ce 0.8 an rb so 0.6 Ab 0.4 HS-(CH2)10-SH DT 0.2 0.0 1000 1100 1200 1300 1400 1500 1600 1700 Wavelength (nm) HS- (CH ) -SH EDT 2 2 5nm and 6 nm InAs nanocrystals HS-CH -φ-CH -SH BDMT Au 2 2 Au 5nm GaAs n-GaAs 50nm AlGaAs semi- insulating GaAs semi-insulating substrate FTIR spectra of GaAs slides with 1,10 Decanethiol Monolayer and with InAs 6 nm NPs connected 0.0025 1,10 Decanethiol+InAs 1/2h 1260 1,10 Decanethiol+InAs 10 Decanethiol+InAs 1h 16(1,10 Decanethiol+InAs one step) 0.0020 1,10 Decanethiol 1,10 Decanethiol e 0.0015 anc rb o s b 0.0010 A 0.0005 0.0000 1340 1320 1300 1280 1260 1240 1220 1200 -1 -0.30 Wavenumber (cm ) GaAs insulator; 1,4 Ethanedithiol (EDT); EDT+InAs(AAC1325S3); 40V; 4 min. CH2 Vibration mode -0.35 -0.40 D (V) -0.45 CP Contact Potential Difference -0.50 (Kelvin Probe)- Traps -0.55 0 500 1000 1500 2000 Time (s) Soreq MOCVD (MOVPE) growth system Growth Machine- Thomas Swan with Vertical Reactor Substrates –Te doped InSb (100) or (100) 20 ooffff towartowardsds (111)(111),, up to 2” wafers Metal Organics- TMSb, TMIn Dopants- Zn for p-type, S or Si for n-type, DEZn and H2S/H2 or SiH4/H2 Soreq Growth methods Stranski-Krastanov growth mode γ 2 > γ 12 + γ 1 + µ1 (d ) γ 1 − surface free energy of deposited material γ − Conventional method 2 surface free energy of substrate γ 12 − interface energy µ1 (d ) − strain energy of the γ 2 < γ 12 + γ 1 + µ1 (d ) layer (SK) Droplet heteroepitaxy (DHE) growth mode First stage of the growth: group III element nano-droplets Interest in the last years formation on the substrate M. Gherasimova et al. Second stage of the growth: APL 85 2346 (2004) reaction of these droplets with one or more group V elements in the gas phase (DHE) Soreq InSb dots on different substrates InSb/GaAs Density: 1x1010 cm-2 Size distribution: 15-40nm Q factor: ~0.35 InSb/GaSb Density: 4x1010 cm-2 Size distribution: 15-50nm Q factor: ~0.1 Growing on InSb/InAs SOG Density: 8x1010 cm-2 Size distribution: 15-25nm Q factor: ~0.4 Soreq PL signal of InSb nanodots on GaAs Eg (InSb) =0.23eV (5.4 µ m) 1 10-6 1 10-6 50 18-20 nm Number of dots 15-40nm dots -7 8 10 PL signal 8 10-7 12-30nm dots 40 12-30nm dots with cap 22-25 nm InSb -7 6 10-7 6 10 10K 30 100mW Bulk -7 30-35 nm 4 10 830nm laser 4 10-7 40-45 nm 20 ~50 nm 2 10-7 -7 2 10 10 0 100 0 100 0 3500 4000 4500 5000 5500 3500 4000 4500 5000 5500 Wavelength [nm] Wavelength [nm] Size and density Blue shift 1 757 dots dots cap 0.8 dots cap dots 332 dots cap x 5 0.6 280 0.4 0.2 136 dots Dots and cap Dots+cap X5 0 3000 4000 5000 Wavelength [nm] Soreq Main idea- Well or dots as a gate FET transistor with Sb based nanodots acting as a gate Ohmic contacts Ohmic contacts FET Infrared radiation Amplified current change Potential change A Photon excites an electron to produce a E = hν measurable voltage QWIP QDIP and - e Voltage MESFET QD First excited bias state x50 Ground state Contact Contact QW Barriers Contact FET Contact Contact FET QD QWIP QDIP QWIP - Mature working technology working at 70K, needs grating. Everything under control. QDIP - Theoretically could work at higher temperatures and absorb normal light. Currently no seen advantages over QWIP. FET QD – Taking all the advantages of the QDIP with improved signal to noise ratio and wider material options. Single photon detector at 77K – A. J. Shields et al., APL 76 3673 (2000) Transistor response to a thin layer of InAsSb (Chiaro, Ron aaman) Accepted for publication in IEEE sensors journal 295B InAsSb#2 black body and Ge filter -4 7 10 -4 6 10 -4 5 10 -4 4 10 I light off 1 [A] -4 The detector on a test chip fabricated in Chiaro 3 10 I Ge 1 [A] 300K I light off 003 [A] -4 2 10 I Ge 003 [A] I light off 03 [A] -4 1 10 I Ge 03 [A] 0 0 10 -4 -2 0 2 4 Voltage [V] Room temperature response Amplified response detectors response 2 150 Laser power transistor only respose 100 50 0 0 -50 -100 1.3 µ m laser no voltage 300K 8 10-6 1 10-7 -2 -150 layer photoresponse 0 5 10 15 20 25 30 time [ms] detectors response Room temperature zero voltage AC 1 squre response black body with Ge filter -6 -8 response of the FET with 10nm 4 10 77K 5 10 InAsSb absorber deposited on the gate area .A 1.3 µm laser modulated by a chopper 0 100 0 -4 -2 0 2 4 Voltage [V] Photo response of the thin InAsSb layer compared with the full detector response, When illuminated with a filtered 1000C blackbody radiation presenting a gain of 100. Nano gold local field enhancement With and WO the nanogold Local field enhancement aa132ss3 Blue shift and nano enhancment aa132ss3 inas nano 10k 100mw different wavelength 8 102 1 103 1 DT+ nano gold solution peak DT 10K 2 532nm 8 10 630nm 6 102 10K solution 830nm Nano gold 6 102 2 4 10 0.5 4 102 2 2 10 2 102 0 100 0 100 0 1000 1200 1400 1600 1800 1000 1200 1400 1600 1800 Wavelength [nm] Wavelength [nm] Building new molecules combined with metal nano particles and semiconductor nano Future work GaAs Building artificial molecules with local field enhancement Combination of the two InAs InSb 10K GaAs 0.0004 100mW 830nm laser Dual peak 16_4_06 PL [mV] 0.0002 0.0000 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Wavelength [ µm] PL signal from the two nano structures Two different worlds? Mesoscopic and nano physics Bulk Most works use one option only: •Semiconductor bulk properties •Quantum ideal calculations nickel 3 Angstroms = 0.3 nm In the real life they all coupled to the bulk environment Very complex relations between our robust world and the nano world The environment effects on quantum properties •Strain •Doping • Bend alignment • Discreet levels coupled to continuum •Life time • Dissipation • Conservation laws InAs nano Are the dots free? molecules GaAs substrate 532nm 820nm Transport from the substrate to the Distance to the substrate nono crystal aa132ss3 inas nano 10k 100mw 532nm dt gaas.InGaAs sensor aa112 inas nano on gold 10k 100mw 820nm Avrage 3 10-7 TM PL BDMT 2 DT H O PL EDT 6 10 2 BMDT 10K PL DT EDT CO 2 10-7 2 2 4 10 532nm 100mW 1 10-7 2 102 0 0 10 0 100 1000 1100 1200 1300 1400 1500 1600 1000 1200 1400 1600 1800 Wavelength [nm] wavelength [nm] life time , transport properties , coupling 820nm - coupling 520nm- transport Future work DNA transport studies 2 DT 530nm EDT 820nm BDMT solution 1 DT EDT BDMT molecule 10K 530nm 00 1000 1200 1400 1600 1800 2000 wavelength [nm] life time , transport properties , coupling Future work DNA transport studies Coupling between the np and the GaAs substrate 1. There is coupling between the np and the GaAs as is evident by the SPV and PL studies. 2. The coupling varies with the molecules- In the order- BDMT>EDT>DT 3. Transport of charges interactions between nano particles polarization aa132ss3 inas nano 10k 100mw 532nm dt TE-TM 4 102 TE TM 10K 2 102 0 100 1000 1200 1400 1600 wavelength [nm] Soreq Substrate effects 1.Lattice mismatch (strain) 2.Energy band-gap alignment Type-I Type-II Staggered Type-III InSb/GaAs InSb/GaSb (Type-II Misaligned) InSb/InAs I.T.
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