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4.  Mid-wavelength infrared heterojunction phototransistors based on type-II InAs/AlSb/GaSb superlattices
A. Haddadi, S. Adhikary, A. Dehzangi, and M. Razeghi
Applied Physics Letters 109, 021107-- July 12, 2016 ...[Visit Journal]
A mid-wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb superlattices on GaSb substrate has been demonstrated. Near a wavelength of 4 μm saturated optical gains of 668 and 639 at 77 and 150 K, respectively, are demonstrated over a wide dynamic range. At 150 K, the unity optical gain collector dark current density and DC current gain are 1 × 10−3 A/cm² and 3710, respectively. This demonstrates the potential for use in high-speed applications. In addition, the phototransistor exhibits a specific detectivity value that is four times higher compared with a state-of-the-art type-II superlattice-based photodiode with a similar cut-off wavelength at 150 K. [reprint (PDF)]
 
4.  High Power, Room Temperature, Continuous-Wave Operation of Quantum Cascade Lasers Grown by GasMBE
A. Evans, J. David, L. Doris, J.S. Yu, S. Slivken and M. Razeghi
SPIE Conference, Jose, CA, Vol. 5359, pp. 188-- January 25, 2004 ...[Visit Journal]
Very high power continuous-wave quantum cascade lasers are demonstrated in the mid-infrared (3 - 6 µm) wavelength range. λ~6 µm high-reflectivity coated QCLs are demonstrated producing over 370 mW continuous-wave power at room temperature with continuous-wave operation up to 333 K. Advanced heterostructure geometries, including the use of a thick electroplated gold, epilayer-side heat sink and a buried-ridge heterostructure are demonstrated to improve laser performance significantly when combined with narrow laser ridges. Recent significant improvements in CW operation are presented and include the development if narrow (9 µm-wide) ridges for high temperature CW operation. GasMBE growth of the strain-balanced λ~6 µm QCL heterostructure is discussed. X-ray diffraction measurements are presented and compared to computer simulations that indicate excellent layer and compositional uniformity of the structure. [reprint (PDF)]
 
4.  High-performance, continuous-wave operation of λ ~ 4.6 μm quantum-cascade lasers above room temperature
J.S. Yu, S. Slivken, A. Evans and M. Razeghi
IEEE Journal of Quantum Electronics, Vol. 44, No. 8, p. 747-754-- August 1, 2008 ...[Visit Journal]
We report the high-performance continuous-wave (CW) operation of 10-μm-wide quantum-cascade lasers (QCLs) emitting at λ ~ 4.6 μm, based on the GaInAs–AlInAs material without regrowth, in epilayer-up and -down bonding configurations. The operational characteristics of QCLs such as the maximum average power, peak output power, CW output power, and maximum CW operating temperature are investigated, depending on cavity length. Also, important device parameters, i.e., the waveguide loss, the transparency current density, the modal gain, and the internal quantum efficiency, are calculated from length-dependent results. For a high-reflectivity (HR) coated 4-mm-long cavity with epilayer-up bonding, the highest maximum average output power of 633 mW is measured at 65% duty cycle, with 469 mW still observed at 100%. The laser exhibits the maximum wall-plug efficiencies of 8.6% and 3.1% at 298 K, in pulsed and CW operatons, respectively. From 298 to 393 K, the temperature dependent threshold current density in pulsed operation shows a high characteristic temperature of 200 K. The use of an epilayer-down bonding further improves the device performance. A CW output power of 685 mW at 288 K is achieved for the 4-micron-long cavity. At 298 K, the output power of 590 mW, threshold current density of 1.52 kA / cm2, and maximum wall-plug efficiency of 3.73% are obtained under CW mode, operating up to 363 K (90 °C). For HR coated 3-micron-long cavities, laser characteristics across the same processed wafer show a good uniformity across the area of 2 x 1 cm2, giving similar output powers, threshold current densities, and emission wavelengths. The CW beam full-width at half-maximum of far-field patterns are 25 degree and 46 degree for the parallel and the perpendicular directions, respectively. [reprint (PDF)]
 
4.  Semiconductor ultraviolet detectors
M. Razeghi and A. Rogalski
SPIE Photonics West '96 Photodetectors: Materials and Devices; Proceedings 2685-- January 27, 1996 ...[Visit Journal]
This paper presents an overview of semiconductor ultraviolet (UV) detectors that are currently available and associated technologies that are undergoing further development. At the beginning, the classification of UV detectors and general requirements imposed on these detectors are presented. Further consideration are restricted to modern semiconductor UV detectors, so the current state-of-the-art of different types of semiconductor UV detectors is presented. Hitherto, the semiconductor UV detectors have been mainly fabricated using Si. Industries such as the aerospace, automotive, petroleum, and others have continuously provided the impetus pushing the development of fringe technologies which are tolerant of increasingly high temperatures and hostile environments. As a result, the main effort are currently directed to a new generation of UV detectors fabricated from wide-band-gap semiconductors between them the most promising are diamond and AlGaN. The latest progress in development of AlGaN UV detectors is finally described in detail. [reprint (PDF)]
 
4.  High operability 1024 x 1024 long wavelength Type-II superlattice focal plane array
A. Haddadi, S.R. Darvish, G. Chen, A.M. Hoang, B.M. Nguyen and M. Razeghi
IEEE Journal of Quantum Electronics (JQE), Vol. 48, No. 2, p. 221-228-- February 10, 2012 ...[Visit Journal]
Electrical and radiometric characterization results of a high-operability 1024 x 1024 long wavelength infrared type-II superlattice focal plane array are described. It demonstrates excellent quantum efficiency operability of 95.8% and 97.4% at operating temperatures of 81 K and 68 K, respectively. The external quantum efficiency is 81% without any antireflective coating. The dynamic range is 37 dB at 81 K and increases to 39 dB at 68 K operating temperature. The focal plane array has noise equivalent temperature difference as low as 27 mK and 19 mK at operating temperatures of 81 K and 68 K, respectively, using f/2 optics and an integration time of 0.13 ms. [reprint (PDF)]
 
4.  High Thermal Stability of κ-Ga2O3 Grown by MOCVD
Junhee Lee, Honghyuk Kim, Lakshay Gautam and Manijeh Razeghi
Lee, J.; Kim, H.; Gautam, L.; Razeghi, M. High Thermal Stability of κ-Ga2O3 Grown by MOCVD. Crystals 2021, 11, 446. https://doi.org/ 10.3390/cryst11040446 ...[Visit Journal]
We report a high thermal stability of kappa gallium oxide grown on c-plane sapphire substrate by metal organic chemical vapor deposition. Kappa gallium oxide is widely known as a metastable polymorph transitioning its phase when subjected to a high temperature. Here, we show the kappa gallium oxide whose phase is stable in a high temperature annealing process at 1000 °C. These oxide films were grown at 690 °C under nitrogen carrier gas. The materials showed high electrical resistivity when doped with silicon, whereas the film conductivity was significantly improved when doped with both indium and silicon. This work provides a pathway to overcoming limitations for the advance in utilizing kappa gallium oxide possessing superior electrical characteristics. [reprint (PDF)]
 
4.  High Detectivity InGaAs/InGaP Quantum-Dot Infrared Photodetectors Grown by Low Pressure Metalorganic Chemical Vapor Deposition
J. Jiang, S. Tsao, T. O'Sullivan, W. Zhang, H. Lim, T. Sills, K. Mi, M. Razeghi, G.J. Brown, and M.Z. Tidrow
Virtual Journal of Nanoscale Science and Technology 9 (12)-- March 29, 2004 ...[Visit Journal][reprint (PDF)]
 
4.  Room Temperature Terahertz and Frequency Combs Based on Intersubband Quantum Cascade Laser Diodes: History and Future
e Manijeh Razeghi , and Quanyong Lu
Manijeh Razeghi, and Quanyong Lu Room Temperature Terahertz and Frequency Combs Based on Intersubband Quantum Cascade Laser Diodes: History and Futur Photonics 2025, 12(1), 79; ...[Visit Journal]
: The year 2024 marks the 30-year anniversary of the quantum cascade laser (QCL), which is becoming the leading laser source in the mid-infrared (mid-IR) range. Since the first demonstration, QCL has undergone tremendous development in terms of the output power, wall plug efficiency, spectral coverage, wavelength tunability, and beam quality. Owing to its unique intersubband transition and fast gain features, QCL possesses strong nonlinearities that makes it an ideal platform for nonlinear photonics like terahertz (THz) difference frequency generation and direct frequency comb generation via fourwave mixing when group velocity dispersion is engineered. The feature of broadband, high-power, and low-phase noise of QCL combs is revolutionizing mid-IR spectroscopy and sensing by offering a new tool measuring multi-channel molecules simultaneously in the µs time scale. While THz QCL difference frequency generation is becoming the only semiconductor light source covering 1–5 THz at room temperature. In this paper, we will introduce the latest research from the Center for Quantum Devices at Northwestern University and briefly discuss the history of QCL, recent progress, and future perspective of QCL research, especially for QCL frequency combs, room temperature THz QCL difference frequency generation, and major challenges facing QCL in the future. [reprint (PDF)]
 
4.  Demonstration of long wavelength infrared Type-II InAs/InAs1-xSbx superlattices photodiodes on GaSb substrate grown by metalorganic chemical vapor deposition
D. H. Wu, A. Dehzangi, Y. Y. Zhang, M. Razeghi
Applied Physics Letters 112, 241103-- June 12, 2018 ...[Visit Journal]
We report the growth and characterization of long wavelength infrared type-II InAs/InAs1−xSbx superlattices photodiodes with a 50% cut-off wavelength at 8.0 μm on GaSb substrate grown by metalorganic chemical vapor deposition. At 77 K, the photodiodes exhibited a differential resistance at zero bias (R0A) 8.0 Ω·cm2, peak responsivity of 1.26 A/W corresponding to a quantum efficiency of 21%. A specific detectivity of 5.4×1010 cm·Hz1/2/W was achieved at 7.5 μm. [reprint (PDF)]
 
4.  High-Average-Power, High-Duty-Cycle (~6 μm) Quantum Cascade Lasers
S. Slivken, A. Evans, J. David, and M. Razeghi
Virtual Journal of Nanoscience & Technology 9-- December 9, 2002 ...[Visit Journal][reprint (PDF)]
 
4.  Very High Average Power Quantum Cascade Lasers by GasMBE
S. Slivken and M. Razeghi
SPIE Conference, San Jose, CA, Vol. 4999, pp. 59-- January 27, 2003 ...[Visit Journal]
Very high average power QCLs are demonstrated within the 5.8 - 9 µm wavelength range. At longer wavelengths, scaling of the power is demonstrated by increasing the number of emitting regions in the waveguide core. At λ = 9 µm, over 3.5 W of peak power per facet has been demonstrated at room temperature for a single 25 µm by 3 mm diode, with an average power of 150 mW at 6% duty cycle. At shorter wavelengths, highly strain-balanced heterostructures are used to create a high coduction band offset and minimize leakage current. At λ = 6 µm, utilizing a high reflective coating and epilayer-down mounting of the laser, we demonstrate 225 mW of average power from a single facet at room temperature. Increasing the conduction band offset further and optimizing the doping in the injector region has led to demonstration of > 250 mW average power (λ = 5.8 µm) at > 50% duty cycle for a 20 µm by 2 mm HR coated diode bonded epilayer-down to a copper heatsink. Also at room temperature, use of Au electroplating and wider ridges has allowed us to further demonstrate without epilayer-down bonding, 0.67 W average power at 17% duty cycle from a single 40 µm by 2 mm HR coated laser. [reprint (PDF)]
 
4.  Continuous-wave operation of λ ~ 4.8 µm quantum-cascade lasers at room temperature
A. Evans, J.S. Yu, S. Slivken, and M. Razeghi
Applied Physics Letters, 85 (12)-- September 20, 2004 ...[Visit Journal]
Continuous-wave (cw) operation of quantum-cascade lasers emitting at λ~4.8 µm is reported up to a temperature of 323 K. Accurate control of layer thickness and strain-balanced material composition is demonstrated using x-ray diffraction. cw output power is reported to be in excess of 370 mW per facet at 293 K, and 38 mW per facet at 323 K. Room-temperature average power measurements are demonstrated with over 600 mW per facet at 50% duty cycle with over 300 mW still observed at 100% (cw) duty cycle. [reprint (PDF)]
 
4.  Study on the effects of minority carrier leakage in InAsSb/InPAsSb double heterostructure
B. Lane, D. Wu, H.J. Yi, J. Diaz, A. Rybaltowski, S. Kim, M. Erdtmann, H. Jeon and M. Razeghi
Applied Physics Letters 70 (11)-- April 17, 1997 ...[Visit Journal]
InAsxSb1−x/InP1−x−yAsxSby double heterostructures have been grown on InAs substrates by metal-organic chemical vapor deposition. The minority carrier leakage to the cladding layers was studied with photoluminescence measurements on the InAsSb/InPAsSb double heterostructures. A carrier leakage model is used to extract parameters related to the leakage current (diffusion-coefficient and length) from experimental results. Using the obtained parameters, the temperature dependence of the threshold current density of InAsSb/InPAsSb double heterostructure lasers is predicted and compared with experimental results. [reprint (PDF)]
 
4.  Deep ultraviolet (254 nm) focal plane array
E. Cicek, Z. Vashaei, R. McClintock, and M. Razeghi
SPIE Proceedings, Conference on Infrared Sensors, Devices and Applications; and Single Photon Imaging II, Vol. 8155, p. 81551O-1-- August 21, 2011 ...[Visit Journal]
We report the synthesis, fabrication and testing of a 320 × 256 focal plane array (FPA) of back-illuminated, solarblind, p-i-n, AlxGa1-xN-based detectors, fully realized within our research laboratory. We implemented a novel pulsed atomic layer deposition technique for the metalorganic chemical vapor deposition (MOCVD) growth of crackfree, thick, and high Al composition AlxGa1-xN layers. Following the growth, the wafer was processed into a 320 × 256 array of 25 μm × 25 μm pixels on a 30 μm pixel-pitch and surrounding mini-arrays. A diagnostic mini-array was hybridized to a silicon fan-out chip to allow the study of electrical and optical characteristics of discrete pixels of the FPA. At a reverse bias of 1 V, an average photodetector exhibited a low dark current density of 1.12×10-8 A·cm-2. Solar-blind operation is observed throughout the array with peak detection occurring at wavelengths of 256 nm and lower and falling off three orders of magnitude by 285 nm. After indium bump deposition and dicing, the FPA is hybridized to a matching ISC 9809 readout integrated circuit (ROIC). By developing a novel masking technology, we significantly reduced the visible response of the ROIC and thus the need for external filtering to achieve solar- and visible-blind operation is eliminated. This allowed the FPA to achieve high external quantum efficiency (EQE): at 254 nm, average pixels showed unbiased peak responsivity of 75 mA/W, which corresponds to an EQE of ~37%. Finally, the uniformity of the FPA and imaging properties are investigated. [reprint (PDF)]
 
4.  Neutron Activation Analysis of an Iranian Cigarette and its Smoke
Z. Abedinzadeh, M. Razeghi and B. Parsa
Z. Abedinzadeh, M. Razeghi and B. Parsa, Journal of Radioanalytical Chemistry, VoL 35 [1977) 373-376-- September 1, 1977 ...[Visit Journal]
Non-destructive neutron activation analysis, employing a high-resolution Ge(Li) detector, was applied to determine the concentration of 24 trace elements in the tobacco of the Zarrin cigarette which is commercially made in Iran. These elements are: Na, K, Sc, Cr, Mn, Fe, Co, Zn, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Au, Hg and Th. The smokes from the combustion of this tobacco and of the cigarette paper were also analysed for these elements and the percentage transference values were calculated. [reprint (PDF)]
 
4.  Investigation of 0.8 μm InGaAsP-GaAs laser diodes with Multiple Quantum Wells
J. Diaz, H. Yi, S. Kim, M. Erdtmann, L.J. Wang, I. Eliashevich, E. Bigan and M. Razeghi
Optoelectronic Integrated Circuit Materials, Physics and Devices, SPIE Conference, San Jose, CA; Proceedings, Vol. 2397-- February 6, 1995 ...[Visit Journal]
In this paper, we studied the effects of the active region structure (one, two and three quantum wells with same total thickness) for high-power InGaAsP-GaAs separate confinement heterostructure lasers emitting at 0.8 μm wavelength. Experimental results for the lasers grown by low pressure metalorganic chemical vapor deposition show excellent agreement with the theoretical model. Total output power of 47 W from an uncoated 1 cm-wide laser bar was achieved in quasi-continuous wave operation [reprint (PDF)]
 
3.  Stranski-Krastanov growth of InGaN quantum dots emitting in green spectra
C. Bayram and M. Razeghi
Applied Physics A: Materials Science and Processing, Vol. 96, No. 2, p. 403-408-- August 1, 2009 ...[Visit Journal]
Self-assembled InGaN quantum dots (QDs) were grown on GaN templates by metalorganic chemical vapor deposition. 2D–3D growth mode transition through Stranski–Krastanov mode was observed via atomic force microscopy. The critical thickness for In0.67Ga0.33N QDs was determined to be four monolayers. The effects of growth temperature, deposition thickness, and V/III ratio on QD formation were examined. The capping of InGaN QDs with GaN was analyzed. Optimized InGaN quantum dots emitted in green spectra at room temperature. [reprint (PDF)]
 
3.  Type-II superlattice photodetectors for MWIR to VLWIR focal plane arrays
M. Razeghi, Y. Wei, A. Hood, D. Hoffman, B.M. Nguyen, P.Y. Delaunay, E. Michel and R. McClintock
SPIE Infrared Technology and Applications Conference, April 17-21, 2006, Orlando, FL Proceedings – Infrared Technology and Applications XXXII, Vol. 6206, p. 62060N-1-- April 21, 2006 ...[Visit Journal]
Results obtained on GaSb/InAs Type-II superlattices have shown performance comparable to HgCdTe detectors, with the promise of higher performance due to reduced Auger recombination and dark current through improvements in device design and material quality. In this paper, we discuss advancements in Type-II IR sensors that cover the 3 to > 30 µm wavelength range. Specific topics covered will be device design and modeling using the Empirical Tight Binding Method (ETBM), material growth and characterization, device fabrication and testing, as well as focal plane array processing and imaging. Imaging has been demonstrated at room temperature for the first time with a 5 µm cutoff wavelength 256×256 focal plane array. [reprint (PDF)]
 
3.  Photoconductance measurements on InTlSb/InSb/GaAs grown by low-pressure metalorganic chemical vapor deposition
P.T. Staveteig, Y.H. Choi, G. Labeyrie, E. Bigan, and M. Razeghi
Applied Physics Letters 64 (4)-- January 24, 1994 ...[Visit Journal]
We report infrared photoconductors based on InTlSb/InSb grown by low‐pressure metalorganic chemical vapor deposition on semi-insulating GaAs substrates. The photoresponse spectrum extends up to 8 μm at 77 K. The absolute magnitude of the photoresponse is measured as a function of bias. The specific detectivity is estimated to be 3×108 Hz½·cm·W-1 at 7 μm wavelength. [reprint (PDF)]
 
3.  Positive and negative luminescence in binary Type-II InAs/GaSb superlattice photodiodes
D. Hoffman and M. Razeghi
SPIE Conference, San Jose, CA, Vol. 6127, pp. 61271H-- January 23, 2006 ...[Visit Journal]
In the present work, we show measurements of both positive and negative luminescence of binary Type-II InAs/GaSb superlattice photodiodes in the 3 to 13 μm spectral range. Through a radiometric calibration technique, we demonstrate temperature independent negative luminescence efficiencies of 45 % in the midwavelength (MWIR) sample from 220 K to 320 K without anti-reflective coating and values reaching 35 % in the long wavelength infrared (LWIR) spectrum sample. [reprint (PDF)]
 
3.  Room temperature operation of 8-12 μm InSbBi infrared photodetectors on GaAs substrates
J.J. Lee, J.D. Kim, and M. Razeghi
Applied Physics Letters 73 (5)-- August 3, 1998 ...[Visit Journal]
We report the room temperature operation of 8–12 μm InSbBi long-wavelength infrared photodetectors. The InSbBi/InSb heterostructures were grown on semi-insulating GaAs (001) substrates by low pressure metalorganic chemical vapor deposition. The voltage responsivity at 10.6 μm was about 1.9 mV/W at room temperature and the corresponding Johnson noise limited detectivity was estimated to be about 1.2×106 cm·Hz½/W. The carrier lifetime derived from the voltage dependent responsivity measurements was about 0.7 ns. [reprint (PDF)]
 
3.  Type-II InAs/GaSb Superlattices and Detectors with Cutoff Wavelength Greater Than 18 μm
M. Razeghi, Y. Wei, A. Gin, G.J. Brown and D. Johnstone
Proceedings of the SPIE, San Jose, CA, Vol. 4650, 111 (2002)-- January 25, 2002 ...[Visit Journal]
The authors report the most recent advances in Type-II InAs/GaSb superlattice materials and photovoltaic detectors. Lattice mismatch between the substrate and the superlattice has been routinely achieved below 0.1%, and less than 0.0043% as the record. The FWHM of the zeroth order peak from x-ray diffraction has been decreased below 50 arcsec and a record of less than 44arcsec has been achieved. High performance detectors with 50% cutoff beyond 18 micrometers up to 26 micrometers have been successfully demonstrated. The detectors with a 50% cut-off wavelength of 18.8 micrometers showed a peak current responsivity of 4 A/W at 80K, and a peak detectivity of 4.510 cm·Hz½·W-1 was achieved at 80K at a reverse bias of 110 mV under 300 K 2(pi) FOV background. Some detectors showed a projected 0% cutoff wavelength up to 28~30 micrometers . The peak responsivity of 3Amp/Watt and detectivity of 4.2510 cm·Hz½·W-1 was achieved under -40mV reverse bias at 34K for these detectors. [reprint (PDF)]
 
3.  Very high performance LWIR and VLWIR type-II InAs/GaSb superlattice photodiodes with M-structure barrier
B.M. Nguyen, D. Hoffman, P.Y. Delaunay, E.K. Huang and M. Razeghi
SPIE Proceedings, Vol. 7082, San Diego, CA 2008, p. 708205-- September 3, 2008 ...[Visit Journal]
LWIR and VLWIR type-II InAs/GaSb superlattice photodetectors have for long time suffered from a high dark current level and a low dynamic resistance which hampers the its emergence to the infrared detection and imaging industry. However, with the use of M-structure superlattice, a new Type-II binary InAs/GaSb/AlSb superlattice design, as an effective blocking barrier, the dark current in type-II superlattice diode has been significantly reduced. We have obtained comparable differential resistance product to the MCT technology at the cut-off wavelength of 10 and 14μm. Also, this new design is compatible with the optical optimization scheme, leading to high quantum efficiency, high special detectivity devices for photon detectors and focal plane arrays. [reprint (PDF)]
 
3.  8.5 μm Room Temperature Quantum Cascade Lasers Grown by Gas-Source Molecular Beam Epitaxy
S. Slivken and M. Razeghi
SPIE Conference, San Jose, CA, -- January 28, 1998 ...[Visit Journal]
We report room-temperature pulsed-mode operation of 8.5 μm quantum cascade lasers grown by gas-source molecular beam epitaxy. The theory necessary to understand the operation of the laser is presented and current problems are analyzed. Very good agreement is shown to exist between theoretical and experimental emission wavelengths. The high- temperature operation is achieved with 1 μs pulses at a repetition rate of 200 Hz. Peak output power in these conditions is in excess of 700 mW per 2 facets at 79 K and 25 mW at 300 K. Threshold current as a function of temperature shows an exponential dependence with T0 equals 188 K for a 1.5 mm cavity. [reprint (PDF)]
 
3.  Impact of scaling base thickness on the performance of heterojunction phototransistors
Arash Dehzangi, Abbas Haddadi, Sourav Adhikary, and Manijeh Razeghi
Nanotechnology 28, 10LT01-- February 2, 2017 ...[Visit Journal]
In this letter we report the effect of vertical scaling on the optical and electrical performance of mid-wavelength infrared heterojunction phototransistors based on type-II InAs/GaSb/AlSb superlattices. The performance of devices with different base thickness was compared as the base was scaled from 60 down to 40 nm. The overall optical performance shows enhancement in responsively, optical gain, and specific detectivity upon scaling the base width. The saturated responsivity for devices with 40 nm bases reaches 8,845 and 9,528 A/W at 77 and 150 K, respectively, which is almost five times greater than devices with 60 nm bases. The saturated optical gain for devices with 40 nm bases is measured as 2,760 at 77 K and 3,081 at 150 K. The devices with 40 nm bases also exhibit remarkable enhancement in saturated current gain, with 17,690 at 77 K, and 19,050 at 150 K. [reprint (PDF)]
 

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