Center for Quantum Devices - Most Downloaded Journal Articles

Page 22 of 30: Prev << 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 >> Next (738 Items)

13.	Scaling in back-illuminated GaN avalanche photodiodes K. Minder, J.L. Pau, R. McClintock, P. Kung, C. Bayram, M. Razeghi and D. Silversmith Applied Physics Letters, Vol. 91, No. 7, p. 073513-1-- August 13, 2007 ...[Visit Journal] Avalanche p-i-n photodiodes of various mesa areas were fabricated on AlN templates for back illumination for enhanced performance through hole-initiated multiplication, and the effects of increased area on device performance were studied. Avalanche multiplication was observed in mesa sizes up to 14,063 µm^2 under linear mode operation. Uniform gain and a linear increase of the dark current with area were demonstrated. [reprint (PDF)]
13.	Well Resolved Room Temperature Photovoltage Spectra of GaAs-GaInP Quantum Wells and Superlattices Xiaoguang He and Manijeh Razeghi Applied Physics Letters 62 (6)-- February 8, 1993 ...[Visit Journal] We report the first well resolved room‐temperature photovoltage spectra due to the sublevel transitions in the GaInP‐GaAs superlattices and multiquantum wells grown by low pressure metalorganic chemical vapor deposition. Sharp well resolved peaks attributed to exciton absorption of the electron‐to‐light hole and electron‐to‐heavy hole have been observed at room temperature. This indicates that GaAs‐GaInP is a promising material for the application of the modulators, optical switches, and optical bistable divices. Satisfactory agreements between experimental measurements and theoretical results have been obtained. These results demonstrate that photovoltage spectroscopy is a simple, but very powerful tool to study quantum confinement structures. [reprint (PDF)]
13.	Demonstration of Zn-Diffused Planar Long-Wavelength Infrared Photodetector Based on Type-II Superlattice Grown by MBE Rajendra K. Saroj, Van Hoang Nguyen, Steven Slivken, Gail J. Brown and Manijeh Razeghi IEEE Journal of Quantum Electronics ...[Visit Journal] We report on a planar long-wavelength infrared photodetector based on InAs/InAs1−xSbx type-II superlattice with zinc diffusion. The superlattice structures were grown by molecular beam epitaxy, followed by a post-growth Zinc diffusion process in a metal-organic chemical vapor deposition reactor. The planar photodetectors showed a peak responsivity of 2.18 A/W, under an applied bias of −20 mV, with a corresponding quantum efficiency of 44.5%, without any anti-reflection coating, and had a 100% cut-off wavelength of 8.5 μm at 77 K temperature. These photodetectors exhibit a specific peak detectivity of 3.0×10^12 cm.Hz^1/2/W, with a dark current density of 1.5 × 10−5 A/cm2 and the differential-resistance-area product of ∼8.6 × 10−1 Ω.cm2, under an applied bias of −20 mV at 77 K. A comparative study between the planar and conventional mesa isolated photodetectors was also carried out. [reprint (PDF)]
13.	2.4 W room temperature continuous wave operation of distributed feedback quantum cascade lasers Q.Y. Lu, Y. Bai, N. Bandyopadhyay, S. Slivken and M. Razeghi Applied Physics Letters, Vol. 98, No. 18, p. 181106-1-- May 4, 2011 ...[Visit Journal] We demonstrate high power continuous-wave room-temperature operation surface-grating distributed feedback quantum cascade lasers at 4.8 μm. High power single mode operation benefits from a combination of high-reflection and antireflection coatings. Maximum single-facet continuous-wave output power of 2.4 W and peak wall plug efficiency of 10% from one facet is obtained at 298 K. Single mode operation with a side mode suppression ratio of 30 dB and single-lobed far field without beam steering is observed. [reprint (PDF)]
13.	High quantum efficiency back-illuminated GaN avalanche photodiodes C. Bayram, J.L. Pau, R. McClintock, M. Razeghi, M.P. Ulmer, and D. Silversmith Applied Physics Letters, Vol. 93, No. 21, p. 211107-1-- November 24, 2008 ...[Visit Journal] Back-illuminated avalanche photodiodes (APDs) composed of heterojunctions of either p-GaN/i-GaN/n-AlGaN or p-GaN/i-GaN/n-GaN/n-AlGaN were fabricated on AlN templates. At low voltage, an external quantum efficiency of 57% at 352 nm with a bandpass response was achieved by using AlGaN in the n-layer. Dependency of gain and leakage current on mesa area for these heterojunction APDs were studied. Back-illumination via different wavelength sources was used to demonstrate the advantages of hole-initiated multiplication in GaN APDs. [reprint (PDF)]
13.	Progress in monolithic, broadband, widely tunable midinfrared quantum cascade lasers Manijeh Razeghi Wenjia Zhou Ryan McClintock Donghai Wu Steven Slivken Optical Engineering 57(1), 011018-- December 1, 2017 ...[Visit Journal] We present recent progress on the development of monolithic, broadband, widely tunable midinfrared quantum cascade lasers. First, we show a broadband midinfrared laser gain realized by a heterogeneous quantum cascade laser based on a strain balanced composite well design of Al_0.63In_0.37As∕Ga_0.35In_0.65As∕ Ga_0.47In_0.53As. Single mode emission between 5.9 and 10.9 μm under pulsed mode operation was realized from a distributed feedback laser array, which exhibited a flat current threshold across the spectral range. Using the broadband wafer, a monolithic tuning between 6.2 and 9.1 μm was demonstrated from a beam combined sampled grating distributed feedback laser array. The tunable laser was utilized for a fast sensing of methane under pulsed operation. Transmission spectra were obtained without any moving parts, which showed excellent agreement to a standard measurement made by a Fourier transform infrared spectrometer. [reprint (PDF)]
13.	High performance focal plane array based on type-II InAs/GaSb superlattice heterostructures P.Y. Delaunay and M. Razeghi SPIE Conference, January 20-25, 2008, San Jose, CA Proceedings – Quantum Sensing and Nanophotonic Devices V, Vol. 6900, p. 69000M-1-10.-- February 1, 2008 ...[Visit Journal] Recent progress in growth techniques, structure design and processing has lifted the performances of Type-II InAs/GaSb superlattice photodetectors. A double heterostructure design, based on a low band gap (11 µm) active region and high band gap (5 µm) superlattice contacts, reduced the sensitivity of the superlattice to surface effects. The heterodiodes with an 11 µm cutoff, passivated with SiO₂, presented similar performances to unpassivated devices and a one order of magnitude increase of the resistivity of the sidewalls, even after flip-chip bonding and underfill. Thanks to this new design and to the inversion of the polarity of the devices, a high performance focal plane array with an 11 µm cutoff was demonstrated. The noise equivalent temperature difference was measured as 26 mK and 19 mK for operating temperatures of 81 K and 67 K. At an integration time of 0.08 ms, the FPA presented a quantum efficiency superior to 50%. [reprint (PDF)]
13.	Ultra-broadband quantum cascade laser, tunable over 760 cm−1, with balanced gain N. Bandyopadhyay, M. Chen, S. Sengupta, S. Slivken, and M. Razeghi Opt. Express 23, 21159-21164 -- August 10, 2015 ...[Visit Journal] A heterogeneous quantum cascade laser, consisting of multiple stacks of discrete wavelength quantum cascade stages, emitting in 5.9-10.9 µm, wavelength range is reported. The broadband characteristics are demonstrated with a distributed-feedback laser array, emitting at fixed frequencies at room temperature, covering an emission range of ~760 cm⁻¹, which is ~59% relative to the center frequency. By appropriate choice of a strained AlInAs/GaInAs material system, quantum cascade stage design and spatial arrangement of stages, the distributed-feedback array has been engineered to exhibit a flat threshold current density across the demonstrated range. [reprint (PDF)]
13.	Tight-binding theory for the thermal evolution of optical band gaps in semiconductors and superlattices S. Abdollahi Pour, B. Movaghar, and M. Razeghi American Physical Review, Vol. 83, No. 11, p. 115331-1-- March 15, 2011 ...[Visit Journal] A method to handle the variation of the band gap with temperature in direct band-gap III–V semiconductors and superlattices using an empirical tight-binding method has been developed. The approach follows closely established procedures and allows parameter variations which give rise to perfect fits to the experimental data. We also apply the tight-binding method to the far more complex problem of band structures in Type-II infrared superlattices for which we have access to original experimental data recently acquired by our group. Given the close packing of bands in small band-gap Type-II designs, k·p methods become difficult to handle, and it turns out that the sp3s* tight-binding scheme is a practical and powerful asset. Other approaches to band-gap shrinkage explored in the past are discussed, scrutinized, and compared. This includes the lattice expansion term, the phonon softening mechanism, and the electron-phonon polaronic shifts calculated in perturbation theory. [reprint (PDF)]
13.	High performance bias-selectable dual-band short-/mid-wavelength infrared photodetectors based on type-II InAs/GaSb/AlSb superlattices A.M. Hoang, G. Chen, A. Haddadi and M. Razeghi SPIE Proceedings, Vol. 8631, p. 86311K-1, Photonics West, San Francisco, CA-- February 5, 2013 ...[Visit Journal] Active and passive imaging in a single camera based on the combination of short-wavelength and mid-wavelength infrared detection is highly needed in a number of tracking and reconnaissance missions. Due to its versatility in band-gap engineering, Type-II InAs/GaSb/AlSb superlattice has emerged as a candidate highly suitable for this multi-spectral detection. In this paper, we report the demonstration of high performance bias-selectable dual-band short-/mid-wavelength infrared photodetectors based on InAs/GaSb/AlSb type-II superlattice with designed cut-off wavelengths of 2 μm and 4 μm. Taking advantages of the high performance short-wavelength and mid-wavelength single color photodetectors, back-to-back p-i-n-n-i-p photodiode structures were grown on GaSb substrate by molecular beam epitaxy. At 150 K, the short-wave channel exhibited a quantum efficiency of 55%, a dark current density of 1.0x10^-9 A/cm² at -50 mV bias voltage, providing an associated shot noise detectivity of 3.0x10¹³ Jones. The mid-wavelength channel exhibited a quantum efficiency of 33% and a dark current density of 2.6x10^-5 A/cm² at 300 mV bias voltage, resulting in a detectivity of 4.0x10¹¹ Jones. The operations of the two absorber channels are selectable by changing the polarity of applied bias voltage. [reprint (PDF)]
13.	Background limited long wavelength infrared type-II InAs/GaSb superlattice photodiodes operating at 110 K B.M. Nguyen, D. Hoffman, E.K. Huang, P.Y. Delaunay, and M. Razeghi Applied Physics Letters, Vol. 93, No. 12, p. 123502-1-- September 22, 2008 ...[Visit Journal] The utilization of the P+-pi-M-N+ photodiode architecture in conjunction with a thick active region can significantly improve long wavelength infrared Type-II InAs/GaSb superlattice photodiodes. By studying the effect of the depletion region placement on the quantum efficiency in a thick structure, we achieved a topside illuminated quantum efficiency of 50% for an N-on-P diode at 8.0 µm at 77 K. Both the double heterostructure design and the application of polyimide passivation greatly reduce the surface leakage, giving an R₀A of 416 Ω·cm² for a 1% cutoff wavelength of 10.52 µm, a Shot–Johnson detectivity of 8.1×10¹¹ cm·Hz^½/W at 77 K, and a background limited operating temperature of 110 K with 300 K background. [reprint (PDF)]
13.	Pressure dependence study of the effective mass in Ga0.47In0.53As/InP heterojunctions D. Gauthier , L. Dmowski, J.C. Portal D. Leadley, M.A. Hopkins , M.A. Brummell , R.J. Nicholas, M. Razeghi, P. Maurel D. Gauthier, L. Dmowski, J.C. Portal, D. Leadley, M.A. Hopkins, M.A. Brummell, R.J. Nicholas, M. Razeghi, P. Maurel, Pressure dependence study of the effective mass in Ga0.47In0.53As/InP heterojunctions, Superlattices and Microstructures, Volume 4, Issue 2, 1988, Pages 201-206-- August 17, 1987 ...[Visit Journal] A study of the effective mass in GaInAs/InP heterojunctions under hydrostatic pressure up to 15 kbars is presented. Earlier results have shown the importance of hydrostatic pressure effects on the band parameters of the heterojunction to explain the experimental decrease of the carrier concentration with pressure at the interface (1). Here magnetophonon resonance experiments are performed to work out the increase of mass with pressure in our samples. The effective mass at atmospheric pressure is deduced from high temperature cyclotron resonance experiments and then used to calculate the frequency of the phonon interacting with the 2D electron gas (wo). The value of wo is found to be dependent on the carrier concentration of the measured samples. The lowest value is found for the highest carrier concentration sample. A band edge effective mass increase of 1 ± .1% kbar is found in the highest carrier concentration sample. This is two times smaller than the rate found experimentally in GaInAs bulk material and slightly smaller than in an AlInAs/GaInAs heterojunction. The experimental increase could be fitted with multiband k.p theory assuming no pressure dependence for the conduction band-valence band matrix element Ep. However at lower concentration a variation of the matrix element Ep with pressure has to be considered. [reprint (PDF)]
13.	Widely Tunable, Single-Mode, High-Power Quantum Cascade Lasers M. Razeghi, B. Gokden, S. Tsao, A. Haddadi, N. Bandyopadhyay, and S. Slivken SPIE Proceedings, Intergreated Photonics: Materials, Devices and Applications, SPIE Microtechnologies Symposium, Prague, Czech Republic, April 18-20, 2011, Vol. 8069, p. 806905-1-- May 31, 2011 ...[Visit Journal] We demonstrate widely tunable high power distributed feedback quantum cascade laser array chips that span 190 nm and 200 nm from 4.4 um to 4.59 um and 4.5 um to 4.7 um respectively. The lasers emit single mode with a very narrow linewidth and side mode suppression ratio of 25 dB. Under pulsed operation power outputs up to 1.85 W was obtained from arrays with 3 mm cavity length and up to 0.95 W from arrays with 2 mm cavity length at room temperature. Continuous wave operation was also observed from both chips with 2 mm and 3 mm long cavity arrays up to 150 mW. The cleaved size of the array chip with 3 mm long cavities was around 4 mm x 5 mm and does not require sensitive external optical components to achieve wide tunability. With their small size and high portability, monolithically integrated DFB QCL Arrays are prominent candidates of widely tunable, compact, efficient and high power sources of mid-infrared radiation for gas sensing. [reprint (PDF)]
13.	EPR investigation of Gd3+ and Eu2+ in the α- and β-phases of lead phosphate M. RAZEGHI, J. P. BUISSON, and B. HOULIE M. RAZEGHI et al.: EPR Investigation of Gd3+ and Eu2+ in Lead Phosphate phys. stat. sol. (b) 96, 283 (1979-- September 1, 1979 ...[Visit Journal] The X-band EPR spectra of Gd3+and Eu2+diluted in Pb3(P04)2crystals are studied. Lead phos-phate exhibits a ferroelastic phase transition a t 180 “C and the EPR spectra obtained in eachphase differ from each other. The spectra are very complex because the zero field splitting hasthe same order of magnitude as the Zeeman term. The spin Hamiltonian parameters and theenergy levels are computed. “Forbidden” or “missing” transitions and line intensities can beexplained. [reprint (PDF)]
13.	Investigation of the Heteroepitaxial Interfaces in the GaInP/GaAs Superlattices by High Resolution X-Ray Diffraction and Dynamical Solutions Xiaoguang He and Manijeh Razeghi Journal of Applied Physics 73 (7)-- April 1, 1993 ...[Visit Journal] Two GaAs/GaInP superlattices grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition have been studied using high resolution x‐ray diffraction measurements and simulations by solving Tagaki–Taupin equations. The strained layers at both interfaces of the GaAs well are identified from the simulations of the measured diffraction patterns. The purging of indium at the interface of GaInP/GaAs accounts for the strained layer at the GaInP/GaAs interface while the pressure difference in the gas lines, which results in the different traveling time to the sample surface, is attributed to the indium‐poor strained layer at the GaAs/GaInP interface. It is shown that high‐resolution x‐ray diffraction measurements combined with a dynamical simulation, are sensitive tools to study the heteroepitaxial interfaces on an atomic layer scale. In addition, the influence of a miscut of the substrate on the measurement is discussed in the article. It is shown that even though the miscut is small, the diffraction geometry is already an asymmetric one. More than 10% error in the superlattice period for a 2° miscut substrate can result when the miscut substrate is considered a symmetric geometry. [reprint (PDF)]
13.	High operating temperature 320 x 256 middle-wavelength infrared focal plane array imaging based on an InAs/InGaAs/InAlAs/InP quantum dot infrared photodetector S. Tsao, H. Lim, W. Zhang, and M. Razeghi Applied Physics Letters, Vol. 90, No. 20, p. 201109-- May 14, 2007 ...[Visit Journal] This letter reports a 320×256 middle-wavelength infrared focal plane array operating at temperatures up to 200 K based on an InAs quantum dot/InGaAs quantum well/InAlAs barrier detector grown on InP substrate by low pressure metal organic chemical vapor deposition. The device's low dark current density and the persistence of the photocurrent up to room temperature enabled the high temperature imaging. The focal plane array had a peak detection wavelength of 4 µm, a responsivity of 34 mA/W, a conversion efficiency of 1.1%, and a noise equivalent temperature difference of 344 mK at an operating temperature of 120 K. [reprint (PDF)]
13.	High magnetic field studies of the two‐dimensional electron gas in GaInAs‐InP superlattices J. C. Portal; R. J. Nicholas; M. A. Brummell; M. Razeghi; M. A. Poisson J. C. Portal, R. J. Nicholas, M. A. Brummell, M. Razeghi, M. A. Poisson; High magnetic field studies of the two‐dimensional electron gas in GaInAs‐InP superlattices. Appl. Phys. Lett. 1 August 1983; 43 (3): 293–295.-- August 1, 1983 ...[Visit Journal] We report the observation of Shubnikov–de Haas oscillations in superlattices of GaInAs and InP, showing evidence of two‐dimensional behavior. The electron g‐factor is deduced from both the criteria for resolution of a spin splitting by comparison with the broadening parameter Γ, and from the tilted field method, and is shown to increase with increasing resolution of the Landau levels in a manner consistent with the theory of Ando and Uemura. In the ultraquantum limit, structure at ν=1/2 and ν=1/3 is observed. [reprint (PDF)]
13.	GaN p-i-n photodiodes with high visible-to-ultraviolet rejection ratio P. Kung, X. Zhang, D. Walker, A. Saxler, and M. Razeghi SPIE Conference, San Jose, CA, -- January 28, 1998 ...[Visit Journal] UV photodetectors are critical components in many applications, including UV astronomy, flame sensors, early missile threat warning and space-to-space communications. Because of the presence of strong IR radiation in these situations, the photodetectors have to be solar blind, i.e. able to detect UV radiation while not being sensitive to IR. Al_xGa_1-xN is a promising material system for such devices. Al_xGa_1-xN materials are wide bandgap semiconductors, with a direct bandgap whose corresponding wavelength can be continuously tuned from 200 to 365 nm. Al_xGa_1-xN materials are thus insensitive to visible and IR radiation whose wavelengths are higher than 365 nm. We have already reported the fabrication and characterization of Al_xGa_1-xN-based photoconductors with a cut-off wavelength tunable from 200 to 365 nm by adjusting the ternary alloy composition. Here, we present the growth and characterization of GaN p-i- n photodiodes which exhibit a visible-to-UV rejection ratio of 6 orders or magnitude. The thin films were grown by low pressure metalorganic chemical vapor deposition. Square mesa structures were fabricated using dry etching, followed by contact metallization. The spectral response, rejection ratio and transient response of these photodiodes is reported. [reprint (PDF)]
13.	High Power Electrically Injected Mid-Infrared Interband Lasers Grown by LP-MOCVD B. Lane and M. Razeghi Journal of Crystal Growth 221 (1-4)-- December 1, 2000[reprint (PDF)]
12.	Schottky barrier heights and conduction-band offsets of In_1-xGa_xAs_1-yP_y lattice matched to GaAs J.K. Lee, Y.H. Cho, B.D. Choe, K.S. Kim, H.I. Jeon, H. Lim and M. Razeghi Applied Physics Letters 71 (7)-- August 18, 1997 ...[Visit Journal] The Schottky barrier heights of Au/In_1−xGa_xAs_1−yP_y contacts have been determined as a function of y by the capacitance–voltage and temperature dependent current–voltage characteristics measurements. The barrier height is observed to increase as y is increased for both n- and p-type materials, with a more rapid increase for the p-type material. The compositional variation of the barrier heights for Au/n-In_1−xGa_xAs_1−yP_y is found to be identical to that of the conduction-band offsets in In_1−xGa_xAs_1−yP_y/GaAs heterojunctions. A possible cause of this phenomenon is also discussed. [reprint (PDF)]
12.	Suppression of surface leakage in gate controlled type-II InAs/GaSb mid-infrared photodetectors G. Chen; B.-M. Nguyen; A.M. Hoang; E.K. Huang; S.R. Darvish; M. Razeghi Proc. SPIE 8268, Quantum Sensing and Nanophotonic Devices IX, 826811 (January 20, 2012)-- January 20, 2012 ...[Visit Journal] One of the biggest challenges of improving the electrical performance in Type II InAs/GaSb superlattice photodetector is suppressing the surface leakage. Surface leakage screens important bulk dark current mechanisms, and brings difficulty and uncertainty to the material optimization and bulk intrinsic parameters extraction such as carrier lifetime and mobility. Most of surface treatments were attempted beyond the mid-infrared (MWIR) regime because compared to the bulk performance, surface leakage in MWIR was generally considered to be a minor factor. In this work, we show that below 150K, surface leakage still strongly affects the electrical performance of the very high bulk performance p-π-M-n MWIR photon detectors. With gating technique, we can effectively eliminate the surface leakage in a controllable manner. At 110K, the dark current density of a 4.7 μm cut-off gated photon diode is more than 2 orders of magnitude lower than the current density in SiO₂ passivated ungated diode. With a quantum efficiency of 48%, the specific detecivity of gated diodes attains 2.5 x 10¹⁴ cm·Hz^1/2/W, which is 3.6 times higher than that of ungated diodes. [reprint (PDF)]
12.	Optical losses of Al-free lasers for λ = 0.808 and 0.98 μm H. Yi, J. Diaz, B. Lane, and M. Razeghi Applied Physics Letters 69 (20)-- November 11, 1996 ...[Visit Journal] In this work, we study the origin of the optical losses in Al‐free InGaAsP/GaAs (λ=0.808 μm) and InGaAs/GaAs/InGaP (λ=0.980 μm) lasers. Theoretical modeling and the experimental results indicate that the scattering of the laser beam by refractive index fluctuation in the alloys is the dominant loss in our lasers, and the loss due to the free‐carrier absorption and scattering by interface roughness are negligible. [reprint (PDF)]
12.	Back-illuminated separate absorption and multiplication GaN avalanche photodiodes J.L. Pau, C. Bayram, R. McClintock, M. Razeghi and D. Silversmith Applied Physics Letters, Vol. 92, No. 10, p. 101120-1-- March 10, 2008 ...[Visit Journal] The performance of back-illuminated avalanche photodiodes with separate absorption and multiplication regions is presented. Devices with an active area of 225 µm² show a maximum multiplication gain of 41,200. The calculation of the noise equivalent power yields a minimum value of 3.3×10⁻¹⁴ W·Hz^−1/2 at a gain of 3000, increasing to 2.0×10⁻¹³ W·Hz^−1/2 at a gain of 41,200. The broadening of the response edge has been analyzed as a function of bias. [reprint (PDF)]
12.	High performance GaAs/GaInP heterostructure bipolar transistors grown by low-pressure metal-organic chemical vapour deposition M Razeghi, F Omnes, M Defour, P Maurel, J Hu, E Wolk and D Pavlidis M Razeghi et al 1990 Semicond. Sci. Technol. 5 278-- December 11, 1989 ...[Visit Journal] The authors report the fabrication of high-quality GaAs/GaInP n-p-n heterojunction bipolar transistors grown by low-pressure metal-organic chemical vapour deposition on semi-insulating substrates. Various structures with homogeneous and graded bases have been fabricated. Doping profiles together with X-ray double diffraction patterns demonstrate the excellent control of growth parameters such as thicknesses, doping levels and interface quality. The static characteristics of the devices show current gains as high as 400, which is the highest value reported in that system [reprint (PDF)]
12.	Deep Fe and intrinsic defect levels in Ga0.47In0.53As/InP K.‐H. Goetz; D. Bimberg; K.‐A. Brauchle; H. Jürgensen; J. Selders; M. Razeghi; E. Kuphal K.‐H. Goetz, D. Bimberg, K.‐A. Brauchle, H. Jürgensen, J. Selders, M. Razeghi, E. Kuphal; Deep Fe and intrinsic defect levels in Ga0.47In0.53As/InP. Appl. Phys. Lett. 1 February 1985; 46-- February 1, 1985 ...[Visit Journal] Two deep traps in Ga0.47In0.53As/InP:Fe at a depth of 110 meV and 150 meV, respectively, are observed for the first time using low‐temperature photoluminescence and deep level transient spectroscopy. The dependence of luminescence intensity on the growth process itself (liquid phase epitaxy, vapor phase epitaxy, and metalorganic chemical vapor deposition) and its parameters (growth temperature, layer thickness) and the substrate doping is reported and leads to the unambigous identification of the 150‐meV acceptorlike trap as being caused by Fe impurities. Fe diffuses from the substrate to the epitaxial layer during the growth process. This outdiffusion is less pronounced for layers grown at lower temperature. The level at 110 meV which is also observed in layers grown on InP:S substrate is tentatively assigned to an intrinsic defect of Ga0.47In0.53As. [reprint (PDF)]

Page 22 of 30: Prev << 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 >> Next (738 Items)