Center for Quantum Devices - Most Downloaded Journal Articles

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11.	Energy harvesting from millimetric ZnO single wire piezo-generators Rogers, D. J.; Carroll, C.; Bove, P.; Sandana, V. E.; Goubert, L.; Largeteau, A.; Teherani, F. Hosseini; Demazeau, G.; McClintock, R.; Drouhin, H.-J.; Razeghi, M. Oxide-based Materials and Devices III. Edited by Teherani, Ferechteh H.; Look, David C.; Rogers, David J. Proceedings of the SPIE, Volume 8263, article id. 82631X, 7 pp. (2012).-- February 9, 2013 ...[Visit Journal] This work reports on investigations into the possibility of harvesting energy from the piezoelectric response of millimetric ZnO rods to movement. SEM & PL studies of hydrothermally grown ZnO rods revealed sizes ranging from 1 - 3 mm x 100 - 400 microns and suggested that each was a wurtzite monocrystal. Studies of current & voltage responses as a function of time during bending with a probe arm gave responses coherent with those reported elsewhere in the literature for ZnO nanowires or micro-rod single wire generators. The larger scale of these rods provided some advantages over such nano- and microstructures in terms of contacting ease, signal level & robustness. [reprint (PDF)]
11.	Very high quantum efficiency in type-II InAs/GaSb superlattice photodiode with cutoff of 12 µm B.M. Nguyen, D. Hoffman, Y. Wei, P.Y. Delaunay, A. Hood and M. Razeghi Applied Physics Letters, Vol. 90, No. 23, p. 231108-1-- June 4, 2007 ...[Visit Journal] The authors report the dependence of the quantum efficiency on device thickness of Type-II InAs/GaSb superlattice photodetectors with a cutoff wavelength around 12 µm. The quantum efficiency and responsivity show a clear delineation in comparison to the device thickness. An external single-pass quantum efficiency of 54% is obtained for a 12 µm cutoff wavelength photodiodes with a -region thickness of 6.0 µm. The R₀A value is kept stable for the range of structure thicknesses allowing for a specific detectivity (2.2×10¹¹ cm·Hz^½/W). [reprint (PDF)]
11.	III-Nitride Optoelectronic Devices: From Ultraviolet Toward Terahertz M. Razeghi IEEE Photonics Journal-Breakthroughs in Photonics 2010, Vol. 3, No. 2, p. 263-267-- April 26, 2011 ...[Visit Journal] We review III-Nitride optoelectronic device technologies with an emphasis on recent breakthroughs. We start with a brief summary of historical accomplishments and then report the state-of-the-art in three key spectral regimes: (1) Ultraviolet (AlGaN-based avalanche photodiodes, single photon detectors, focal plane arrays, and light emitting diodes), (2) Visible (InGaN-based solid state lighting, lasers, and solar cells), and (3) Near-, mid-infrared, and terahertz (AlGaN/GaN-based gap-engineered intersubband devices). We also describe future trends in III-Nitride optoelectronic devices. [reprint (PDF)]
11.	Room temperature continuous wave, monolithic tunable THz sources based on highly efficient mid-infrared quantum cascade lasers Quanyong Lu, Donghai Wu, Saumya Sengupta, Steven Slivken, Manijeh Razeghi Nature Scientific Reports 6, Article number: 23595-- March 24, 2016 ...[Visit Journal] A compact, high power, room temperature continuous wave terahertz source emitting in a wide frequency range (ν ~ 1–5 THz) is of great importance to terahertz system development for applications in spectroscopy, communication, sensing, and imaging. Here, we present a strong-coupled strain-balanced quantum cascade laser design for efficient THz generation based on intracavity difference frequency generation. Room temperature continuous wave emission at 3.41 THz with a side-mode suppression ratio of 30 dB and output power up to 14 μW is achieved with a wall-plug efficiency about one order of magnitude higher than previous demonstrations. With this highly efficient design, continuous wave, single mode THz emissions with a wide frequency tuning range of 2.06–4.35 THz and an output power up to 4.2 μW are demonstrated at room temperature from two monolithic three-section sampled grating distributed feedback-distributed Bragg reflector lasers. [reprint (PDF)]
11.	Room temperature quantum cascade lasers with 27% wall plug efficiency Y. Bai, N. Bandyopadhyay, S. Tsao, S. Slivken and M. Razeghi Applied Physics Letters, Vol. 98, No. 18, p. 181102-1-- May 3, 2011 ...[Visit Journal] Using the recently proposed shallow-well design, we demonstrate InP based quantum cascade lasers (QCLs) emitting around 4.9 μm with 27% and 21% wall plug efficiencies in room temperature (298 K) pulsed and continuous wave (CW) operations, respectively. The laser core consists of 40 QCL-stages. The highest cw efficiency is obtained from a buried-ridge device with a ridge width of 8 μm and a cavity length of 5 mm. The front and back facets are antireflection and high-reflection coated, respectively. The maximum single facet cw power at room temperature amounts to 5.1 W. [reprint (PDF)]
11.	Tunability of intersubband absorption from 4.5 to 5.3 µm in a GaN/Al_0.2Ga_0.8N superlattices grown by metalorganic chemical vapor deposition N. Péré-Laperne, C. Bayram, L. Nguyen-Thê, R. McClintock, and M. Razeghi Applied Physics Letters, Vol. 95, No. 13, p. 131109-- September 28, 2009 ...[Visit Journal] Intersubband (ISB) absorption at wavelengths as long as 5.3 µm is realized in GaN/Al_0.2Ga_0.8N superlattices grown by metalorganic chemical vapor deposition. By employing low aluminum content Al_0.2Ga_0.8N barriers and varying the well width from 2.6 to 5.1 nm, ISB absorption has been tuned from 4.5 to 5.3 µm. Theoretical ISB absorption and interband emission models are developed and compared to the experimental results. The effects of band offsets and the piezoelectric fields on these superlattices are investigated. [reprint (PDF)]
11.	On the interface properties of ZnO/Si electroluminescent diodes J.L. Pau, J. Piqueras, D.J. Rogers, F. Hosseini Teherani, K. Minder, R. McClintock, and M. Razeghi Journal of Applied Physics, Vol. 107, No. 3, p. 033719-1-- February 1, 2010 ...[Visit Journal] ZnO layers grown on n⁻–Si(100), n⁺–Si(100), and n^––Si(111) substrates by pulsed-laser deposition were found to give electroluminescence. Light emission was observed in the form of discrete spots for currents over 1 mA with a white appearance to the naked eye. The intensity of these spots showed an erratic behavior over time, appearing and disappearing at random, while showing an associated random telegraph noise in the current signal. Regardless the substrate used, the electroluminescence spectra had a main broadband emission centered at about 600 nm and a relatively small peak at around 380 nm which corresponds to the energy of ZnO near band edge emission. Furthermore, the devices exhibited rectifying characteristics, whose current blocking direction depended on the substrate orientation. Optimization of ZnO conductivity and performing sample growth in N₂ ambient were found to be critical to enhance the emission intensity. Rutherford backscattering characterization revealed the existence of an intermixed region at the interface between ZnO and Si. To study the electronic properties at the interface, frequency dependent capacitance measurements were carried out. The junction capacitance became frequency dependent at the bias voltages at which light emission occurs due to the relatively slow trapping and generation processes at deep centers. These centers are believed to play an important role in the mechanism of light emission. [reprint (PDF)]
11.	High-Performance Type-II InAs/GaSb Superlattice Photodiodes with Cutoff Wavelength Around 7 µm Y. Wei, A. Hood, H. Yau, V. Yazdanpanah, M. Razeghi, M.Z. Tidrow and V. Nathan Applied Physics Letters, 86 (9)-- February 28, 2005 ...[Visit Journal] We report the most recent result in the area of type-II InAs/GaSb superlattice photodiodes that have a cutoff wavelength around 7 µm at 77 K. Superlattice with a period of 40 Å lattice matched to GaSb was realized using Ga_xIn_1–x type interface engineering technique. Compared with significantly longer period superlattices, we have reduced the dark current density under reverse bias dramatically. For a 3 µm thick structure, using sulfide-based passivation, the dark current density reached 2.6×10^–5 A/cm² at –3 V reverse bias at 77 K. At this temperature the photodiodes have R₀A of 9300 Ω·cm² and a thermally limited zero bias detectivity of 1×10¹² cm·Hz^½/W. The 90%–10% cutoff energy width was only 16.5 meV. The devices did not show significant dark current change at 77 K after three months storage in the atmosphere. [reprint (PDF)]
11.	GaN-based nanostructured photodetectors J.L. Pau, C. Bayram, P. Giedraitis, R. McClintock, and M. Razeghi SPIE Proceedings, San Jose, CA Volume 7222-14-- January 26, 2009 ...[Visit Journal] The use of nanostructures in semiconductor technology leads to the observation of new phenomena in device physics. Further quantum and non-quantum effects arise from the reduction of device dimension to a nanometric scale. In nanopillars, quantum confinement regime is only revealed when the lateral dimensions are lower than 50 nm. For larger mesoscopic systems, quantum effects are not observable but surface states play a key role and make the properties of nanostructured devices depart from those found in conventional devices. In this work, we present the fabrication of GaN nanostructured metal-semiconductor-metal (MSM) and p-i-n photodiodes (PIN PDs) by e-beam lithography, as well as the investigation of their photoelectrical properties at room temperature. The nanopillar height and diameter are about 520 nm and 200 nm, respectively. MSMs present dark currents densities of 0.4 A/cm² at ±100 V. A strong increase of the optical response with bias is observed, resulting in responsivities higher than 1 A/W. The relationship between this gain mechanism and surface states is discussed. PIN PDs yield peak responsivities (R_peak) of 35 mA/W at -4 V and show an abnormal increase of the response (R_peak > 100 A/W) under forward biases. [reprint (PDF)]
11.	Spatial Noise and Correctability of Type-II InAs/GaSb Focal Plane Arrays P.Y. Delaunay and M. Razeghi IEEE Journal of Quanutm Electronics, April 2010, Vol. 46, No. 4, p. 584-588-- April 1, 2010 ...[Visit Journal] A long wavelength infrared focal plane array based on Type-II InAs/GaSb superlattices was fabricated and characterized at 80 K. The noise equivalent temperature difference of the array was measured as low as 23 mK (f# = 2), for an integration time of 0.129 ms. The spatial noise of the array was dominated by the nonuniformity of the illumination through the circular aperture. A standard two-point nonuniformity correction improved the inhomogeneity equivalent temperature difference to 16 mK. The correctability just after calibration was 0.6. The long-term stability time was superior to 25 hours. [reprint (PDF)]
11.	Persistent photoconductivity in Ga0.49In0.51P/GaAs heterojunctions S. Ben Amor; L. Dmowski; J. C. Portal; N. J. Pulsford; R. J. Nicholas; J. Singleton; M. Razeghi J. Appl. Phys. 65, 2756–2760 (1989-- November 18, 1988 ...[Visit Journal] We have studied the persistent photoconductivity (PPC) effect in Ga0.49 Ino. sl P IGaAs heterostructures. Through time- and temperature-dependent Hall effect, we observe very small relaxation rates and the PPC remains observable at room temperature. Optical experiments show an optical energy threshold of 1.15 e V and an infrared quenching of the ppc. Thermal cycling of the samples strongly affects the PPC and the quenching temperature. The center responsible for the observed PPC, therefore, appears related to defects, Most of our observations are qualitatively understood in a large lattice relaxation DX-like center approach. However, the origin of the high quenching temperature remains to be explained. [reprint (PDF)]
11.	Electrically pumped photonic crystal distributed feedback quantum cascade lasers Y. Bai, P. Sung, S.R. Darvish, W. Zhang, A. Evans, S. Slivken, and M. Razeghi SPIE Conference, January 20-25, 2008, San Jose, CA Proceedings – Quantum Sensing and Nanophotonic Devices V, Vol. 6900, p. 69000A-1-8.-- February 1, 2008 ...[Visit Journal] We demonstrate electrically pumped, room temperature, single mode operation of photonic crystal distributed feedback (PCDFB) quantum cascade lasers emitting at ~ 4.75 µm. Ridge waveguides of 50 µm and 100 µm width were fabricated with both PCDFB and Fabry-Perot feedback mechanisms. The Fabry-Perot device has a broad emitting spectrum and a broad far-field character. The PCDFB devices have primarily a single spectral mode and a diffraction limited far field characteristic with a full angular width at half-maximum of 4.8 degrees and 2.4 degrees for the 50 µm and 100 µm ridge widths, respectively. [reprint (PDF)]
11.	Metalorganic chemical vapor deposition of monocrystalline GaN thin films on β-LiGaO2substrates P. Kung, A. Saxler, X. Zhang, D. Walker, R. Lavado, and M. Razeghi Applied Physics Letters 69 (14)-- September 30, 1996 ...[Visit Journal] We report the metalorganic chemical vapor deposition growth and characterization of monocrystalline GaN thin films on β-LiGaO₂ substrates. The influence of the growth temperature on the crystal quality was studied. The structural, electrical, and optical properties of the films were assessed through scanning electron microscopy, x-ray diffraction, Hall measurements, optical transmission, photoluminescence. [reprint (PDF)]
11.	Type-II superlattice-based heterojunction phototransistors for high speed applications Jiakai Li, Arash Dehzangi, Donghai Wu, Ryan McClintock, Manijeh Razeghi Infrared Physics and Technology 108, 1033502-- May 2, 2020 ...[Visit Journal] In this study, high speed performance of heterojunction phototransistors (HPTs) based on InAs/GaSb/AlSb type-II superlattice with 30 nm base thickness and 50% cut-off wavelength of 2.0 μm at room temperature are demonstrated. We studied the relationship between -3 dB cut-off frequency of these HPT versus mesa size, applied bias, and collector layer thickness. For 8 μm diameter circular mesas HPT devices with a 0.5 μm collector layer, under 20 V applied bias voltage, we achieved a -3 dB cut-off frequency of 2.8 GHz. [reprint (PDF)]
11.	Reliability of strain-balanced Ga_0.331In_0.669As/Al_0.659In_0.341As/InP quantum-cascade lasers under continuous-wave room-temperature operation A. Evans and M. Razeghi Applied Physics Letters, 88 (26)-- June 26, 2006 ...[Visit Journal] Constant current aging is reported for two randomly selected high-reflectivity-coated QCLs with an output power over 100 mW. QCLs are tested under continuous-wave operation at a heat sink temperature of 298 K(25 °C) corresponding to an internal temperature of 378 K (105 °C). Over 4000 h of continuous testing is reported without any decrease in output power. [reprint (PDF)]
11.	InTlSb alloys for infrared detection E. Bigan, Y.H. Choi, G. Labeyrie, and M. Razeghi Proceedings, SPIE Nonlinear Optics for High-Speed Electronics and Optical Frequency Conversion, Vol. 2145-- January 24, 1994 ...[Visit Journal] InTISb alloys have been grown by low-pressure metalorganic chemical vapor deposition, and characterized. Photoconductors exhibit a cutoff wavelength that can be tailored from 5.5 μm up to 9 μm by varying the thallium content. Experimental observations suggest that this can be further extended by increasing the thallium content. An InTISb photoconductor having a 9 μm cutoff wavelength exhibited a D* of 10⁹ cm·Hz^½·W^-1 at 7 μm operating wavelength. [reprint (PDF)]
11.	Surface leakage reduction in narrow band gap type-II antimonide-based superlattice photodiodes E.K. Huang, D. Hoffman, B.M. Nguyen, P.Y. Delaunay and M. Razeghi Applied Physics Letters, Vol. 94, No. 5, p. 053506-1-- February 2, 2009 ...[Visit Journal] Inductively coupled plasma (ICP) dry etching rendered structural and electrical enhancements on type-II antimonide-based superlattices compared to those delineated by electron cyclotron resonance (ECR) with a regenerative chemical wet etch. The surface resistivity of 4×10⁵ Ω·cm is evidence of the surface quality achieved with ICP etching and polyimide passivation. By only modifying the etching technique in the fabrication steps, the ICP-etched devices with a 9.3 µm cutoff wavelength revealed a diffusion-limited dark current density of 4.1×10⁻⁶ A/cm² and a maximum differential resistance at zero bias in excess of 5300 Ω·cm² at 77 K, which are an order of magnitude better in comparison to the ECR-etched devices. [reprint (PDF)]
11.	Schottky MSM Photodetectors on GaN Films Grown on Sapphire by Lateral Epitaxial Overgrowth P. Kung, D. Walker, P. Sandvik, M. Hamilton, J. Diaz, I.H. Lee and M. Razeghi SPIE Conference, San Jose, CA, -- January 27, 1999 ...[Visit Journal] We report the growth and characterization of Schottky based metal-semiconductor-metal ultraviolet photodetectors fabricated on lateral epitaxially overgrown GaN films. The lateral epitaxial overgrowth of GaN was carried out on basal plane sapphire substrates by low pressure metalorganic chemical vapor deposition and exhibited lateral growth rates more than 5 times as high as vertical growth rates. The spectral responsivity, the dependence on bias voltage, on incident optical power, and the time response of these photodetectors have been characterized. Two detector orientations were investigated: one with the interdigitated finger pattern parallel and the other perpendicular to the underlying SiO_x mask stripes. [reprint (PDF)]
11.	InAsSb/InAsP strained-layer superlattice injection lasers operating at 4.0 μm grown by metal-organic chemical vapor deposition B. Lane, Z. Wu, A. Stein, J. Diaz, and M. Razeghi Applied Physics Letters 74 (23)-- June 7, 1999 ...[Visit Journal] We report high power mid-infrared electrical injection operation of laser diodes based on InAsSb/InAsP strained-layer superlattices grown on InAs substrate by metal-organic chemical vapor deposition. The broad-area laser diodes with 100 μm aperture and 1800 μm cavity length demonstrate peak output powers of 546 and 94 mW in pulsed and cw operation respectively at 100 K with a threshold current density as low as 100 A/cm². [reprint (PDF)]
11.	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)]
11.	Intersubband hole absorption in GaAs-GaInP Quantum Wells grown by Gas Source Molecular Beam Epitaxy J. Hoff, C. Jelen, S. Slivken, E. Michel, O. Duchemin, E. Bigan, and M. Razeghi with G. Brown and S.M. Hegde (Wright Laboratory) Applied Physics Letters 65 (9)-- August 29, 1994 ...[Visit Journal] P-doped GaAs‐GaInP quantum wells have been grown on GaAs substrate by gas source molecular beam epitaxy. Structural quality has been evidenced by x-ray diffraction. A narrow low-temperature photoluminescence full width at half‐maximum has been measured. Strong hole intersubband absorption has been observed at 9 μm, and its dependence on light polarization has been investigated. [reprint (PDF)]
11.	Demonstration of Planar Type-II Superlattice-Based Photodetectors Using Silicon Ion-Implantation Arash Dehzangi, Donghai Wu, Ryan McClintock, Jiakai Li, Alexander Jaud and Manijeh Razeghi Photonics 2020, 7(3), 68; https://doi.org/10.3390/photonics7030068-- September 3, 2020 ...[Visit Journal] In this letter, we report the demonstration of a pBn planar mid-wavelength infrared photodetectors based on type-II InAs/InAs1−xSbx superlattices, using silicon ion-implantation to isolate the devices. At 77 K the photodetectors exhibited peak responsivity of 0.76 A/W at 3.8 µm, corresponding to a quantum efficiency, without anti-reflection coating, of 21.5% under an applied bias of +40 mV with a 100% cut-off wavelength of 4.6 µm. With a dark current density of 5.21 × 10−6 A/cm2, under +40 mV applied bias and at 77 K, the photodetector exhibited a specific detectivity of 4.95 × 1011 cm·Hz1/2/W. [reprint (PDF)]
11.	Planar nBn type-II superlattice mid-wavelength infrared photodetectors using zinc ion-implantation Arash Dehzangi, Donghai Wu, Ryan McClintock, Jiakai Li, and Manijeh Razeghi Appl. Phys. Lett. 116, 221103 https://doi.org/10.1063/5.0010273-- June 2, 2020 ...[Visit Journal] In this Letter, we report the demonstration of zinc ion-implantation to realize planar mid-wavelength infrared photodetectors based on type-II InAs/InAs1−xSbx superlattices. At 77 K, the photodetectors exhibit a peak responsivity of 0.68 A/W at 3.35 μm, corresponding to a quantum efficiency of 23.5% under Vb = −80 mV, without anti-reflection coating; these photodetectors have a 100% cutoff wavelength of 4.28 μm. With an R0 × A value of 1.53 × 104 Ω cm2 and a dark current density of 1.23 × 10−6 A/cm2 under an applied bias of −80 mV at 77 K, the photodetectors exhibit a specific detectivity of 9.12 × 1011 cm·Hz1/2/W. [reprint (PDF)]
11.	GaInN/GaN Multi-Quantum Well Laser Diodes Grown by Low-Pressure Metalorganic Chemical Vapor Deposition P. Kung, A. Saxler, D. Walker, A. Rybaltowski, X. Zhang, J. Diaz, and M. Razeghi MRS Internet Journal of Nitride Semiconductor Research 3 (1)-- January 1, 1998 ...[Visit Journal] We report the growth, fabrication and characterization of GaInN/GaN multi-quantum well lasers grown on (00·1) sapphire substrates by low pressure metalorganic chemical vapor deposition. The threshold current density of a 1800 µm long cavity length laser was 1.4 kA/cm² with a threshold voltage of 25 V. These lasers exhibited series resistances of 13 and 14 Ω at 300 and 79 K, respectively. [reprint (PDF)]
11.	Thermal conductivity tensors of the cladding and active layers of antimonide infrared lasers and detectors Chuanle Zhou, I. Vurgaftman, C. L. Canedy, C. S. Kim, M. Kim, W. W. Bewley, C. D. Merritt, J. Abell, J. R. Meyer, A. Hoang, A. Haddadi, M. Razeghi, and M. Grayson Optical Materials Express. 2013;3(10):1632-1640.-- October 1, 2013 ...[Visit Journal] The in-plane and cross-plane thermal conductivities of the cladding layers and active quantum wells of interband cascade lasers and type-II superlattice infrared detector are measured by the 2-wire 3ω method. The layers investigated include InAs/AlSb superlattice cladding layers, InAs/GaInSb/InAs/AlSb W-active quantum wells, an InAs/GaSb superlattice absorber, an InAs/GaSb/AlSb M-structure, and an AlAsSb digital alloy. The in-plane thermal conductivity of the InAs/AlSb superlattice is 4-5 times higher than the cross-plane value. The isotropic thermal conductivity of the AlAsSb digital alloy matches a theoretical expectation, but it is one order of magnitude lower than the only previously-reported experimental value. [reprint (PDF)]

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