Page 23 of 31:  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 31  >> Next  (769 Items)

14.  ZnO Thin Film Templates for GaN-based Devices
D.J. Rogers, F. Hosseini Teherani, A. Yasan, R. McClintock, K. Mayes, S.R. Darvish, P. Kung, M. Razeghi and G. Garry
SPIE Conference, Jose, CA, Vol. 5732, pp. 412-- January 22, 2005 ...[Visit Journal]
GaN-based optoelectronic devices are plagued by a tendency to non-radiative transitions linked to defects in the active layers. ZnO is promising as a substrate material for GaN because it has the same wurtzite structure and a relatively small lattice mismatch (~1.8%). In this paper, we discuss use of ZnO thin films as templates for GaN based LED. [reprint (PDF)]
 
14.  Kinetics of photoconductivity in n-type GaN photodetector
P. Kung, X. Zhang, D. Walker, A. Saxler, J. Piotrowski, A. Rogalski, and M. Razeghi
Applied Physics Letters 67 (25)-- December 18, 1995 ...[Visit Journal]
High-quality ultraviolet photoconductive detectors have been fabricated using GaN layers grown by low-pressure metalorganic chemical vapor deposition on (11⋅0) sapphire substrates. The spectral responsivity remained nearly constant for wavelengths from 200 to 365 nm and dropped sharply by almost three orders of magnitude for wavelengths longer than 365 nm. The kinetics of the photoconductivity have been studied by the measurements of the frequency‐dependent photoresponse and photoconductivity decay. Strongly sublinear response and excitation‐dependent response time have been observed even at relatively low excitation levels. This can be attributed to redistribution of the charge carriers with increased excitation level. [reprint (PDF)]
 
14.  High performance antimony based type-II superlattice photodiodes on GaAs substrates
B.M. Nguyen, D. Hoffman, E.K. Huang, P.Y. Delaunay, and M. Razeghi
SPIE Porceedings, Vol. 7298, Orlando, FL 2009, p. 72981T-- April 13, 2009 ...[Visit Journal]
In recent years, Type-II InAs/GaSb superlattices grown on GaSb substrate have achieved significant advances in both structural design and material growth, making Type-II superlattice infrared detector a rival competitor to the state-of-the-art MCT technology. However, the limited size and strong infrared absorption of GaSb substrates prevent large format type-II superlattice infrared imagers from being realized. In this work, we demonstrate type-II superlattices grown on GaAs substrates, which is a significant step toward third generation infrared imaging at low cost. The device performances of Type-II superalttice photodetectors grown on these two substrates are compared. [reprint (PDF)]
 
14.  Dark current reduction in microjunction-based double electron barrier type-II InAs/InAsSb superlattice long-wavelength infrared photodetectors
Romain Chevallier, Abbas Haddadi, & Manijeh Razeghi
Scientific Reports 7, Article number: 12617-- October 3, 2017 ...[Visit Journal]
Microjunction InAs/InAsSb type-II superlattice-based long-wavelength infrared photodetectors with reduced dark current density were demonstrated. A double electron barrier design was employed to reduce both bulk and surface dark currents. The photodetectors exhibited low surface leakage after passivation with SiO2, allowing the use of very small size features without degradation of the dark current. Fabricating microjunction photodetectors (25 × 25 µm² diodes with 10 × 10 µm² microjunctions) in combination with the double electron barrier design results in a dark current density of 6.3 × 10−6 A/cm² at 77 K. The device has an 8 µm cut-off wavelength at 77 K and exhibits a quantum efficiency of 31% for a 2 µm-thick absorption region, which results in a specific detectivity value of 1.2 × 1012 cm·Hz½/W. [reprint (PDF)]
 
14.  Molecular Beam Epitaxial Growth of High Quality InSb
E. Michel, G. Singh, S. Slivken, C. Besikci, P. Bove, I. Ferguson, and M. Razeghi
Applied Physics Letters 65 (26)-- December 26, 1994 ...[Visit Journal]
In this letter we report on the growth of high quality InSb by molecular beam epitaxy that has been optimized using reflection high energy electron diffraction. A 4.8 µm InSb layer grown on GaAs at a growth temperature of 395 °C and a III/V incorporation ratio of 1:1.2 had an x-ray rocking curve of 158 arcsec and a Hall mobility of 92,300 cm²·V−1 at 77 K. This is the best material quality obtained for InSb nucleated directly onto GaAs reported to date. [reprint (PDF)]
 
14.  Solar-Blind Deep UV Avalanche Photodetectors Using Reduced Area Epitaxy
Lakshay Gautam , Junhee Lee, Michael Richards, and Manijeh Razeghi ,
Lakshay Gautam, Manijeh Razeghi, IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 59, NO. 6, 10.1109/JQE.2023.3325254 ...[Visit Journal]
We report high gain avalanche photodetectors operating in the deep UV wavelength regime. The high gain was leveraged through reduced area epitaxy by patterning AlN on Sapphire substrate. This helps in a substantial reduction of crack formation due to overgrowth on individually isolated AlN mesas. Reproducible gain on the order of 105 was reported for multiple diodes in different areas of 320 × 256 focal plane array. [reprint (PDF)]
 
14.  Gain-length scaling in quantum dot/quantum well infrared photodetectors
T. Yamanaka, B. Movaghar, S. Tsao, S. Kuboya, A. Myzaferi and M. Razeghi
Applied Physics Letters, Vol. 95, No. 9-- August 31, 2009 ...[Visit Journal]
The gain in quantum dot/quantum well infrared photodetectors is investigated. The scaling of the gain with device length has been analyzed, and the behavior agrees with the previously proposed model. We conclude that we understand the gain in the low bias region, but in the high field region, discrepancies remain. An extension of the gain model is presented to cover the very high electric field region. The high field data are compared to the extended model and discussed. [reprint (PDF)]
 
14.  Use of Sacrificial Zinc Oxide Template Layers for Epitaxial Lift-Off of Yttria-Stabilised Zirconia Thin Films
D. J. Rogers, T. Maroutian, V. E. Sandana, P. Lecoeur, F. H. Teherani, P. Bove and M. Razeghi
Proc. of SPIE 11687, 116872C (2021) ...[Visit Journal]
275 nm-thick Yttria-stabilised zirconia (YSZ) layers were grown on 240 nm-thick epitaxial (0002)-oriented ZnO buffer layers on c-sapphire substrates by pulsed laser deposition (PLD). X-ray diffraction (XRD) studies revealed high quality epitaxial growth with the YSZ having a preferential (111) orientation and a root mean square surface roughness of 1.4 nm over an area of 10 um x 10 um. The YSZ top surface was then temporary bonded to an Apiezon W wax carrier and the sample was immersed in 0.1M HCl so as to preferentially etch/dissolve away the ZnO underlayer and release of the YSZ from the sapphire substrate. XRD revealed only the characteristic (111) peak of YSZ after lift-off and thus confirmed both the dissolution of the ZnO and the preservation of the crystallographic integrity of the YSZ on the wax carrier. Optical and Atomic Force Microscopy revealed some buckling, roughening and cracking of the lifted YSZ, however, which was probably due to tensile epitaxial strain release. [reprint (PDF)]
 
14.  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)]
 
14.  Antimonide-Based Type II Superlattices: A Superior Candidate for the Third Generation of Infrared Imaging Systems
M. Razeghi, A. Haddadi, A.M. Hoang, G. Chen, S. Bogdanov, S.R. Darvish, F. Callewaert, P.R. Bijjam, and R. McClintock
Journal of ELECTRONIC MATERIALS, Vol. 43, No. 8, 2014-- August 1, 2014 ...[Visit Journal]
Type II superlattices (T2SLs), a system of interacting multiquantum wells,were introduced by Nobel Laureate L. Esaki in the 1970s. Since then, this material system has drawn a lot of attention, especially for infrared detection and imaging. In recent years, the T2SL material system has experienced incredible improvements in material growth quality, device structure design, and device fabrication techniques that have elevated the performance of T2SL-based photodetectors and focal-plane arrays (FPAs) to a level comparable to state-of-the-art material systems for infrared detection and imaging, such as mercury cadmium telluride compounds. We present the current status of T2SL-based photodetectors and FPAs for imaging in different infrared regimes, from short wavelength to very long wavelength, and dual-band infrared detection and imaging, as well as the future outlook for this material system. [reprint (PDF)]
 
14.  State-of-the-art Type II Antimonide-based superlattice photodiodes for infrared detection and imaging
M. Razeghi, B.M. Nguyen, P.Y. Delaunay, E.K. Huang, S. Abdollahi Pour, P. Manurkar, and S. Bogdanov
SPIE Proceedings, Nanophotonics and Macrophotonics for Space Environments II, San Diego, CA, Vol. 7467, p. 74670T-1-- August 5, 2009 ...[Visit Journal]
Type-II InAs/GaSb Superlattice (SL), a system of multi interacting quantum wells was first introduced by Nobel Laureate L. Esaki in the 1970s. Since then, this low dimensional system has drawn a lot of attention for its attractive quantum mechanics properties and its grand potential for the emergence into the application world, especially in infrared detection. In recent years, Type-II InAs/GaSb superlattice photo-detectors have experienced significant improvements in material quality, structural designs and imaging applications which elevated the performances of Type-II InAs/GaSb superlattice photodetectors to a comparable level to the state-of-the-art Mercury Cadmium Telluride. We will present in this talk the current status of the state-of-the-art Type II superlattice photodetectors and focal plane arrays, and the future outlook for this material system. [reprint (PDF)]
 
14.  Growth of “moth-eye” ZnO nanostructures on Si(111), c-Al2O3, ZnO and steel substrates by pulsed laser deposition
Vinod E. Sandana, David J. Rogers, Ferechteh Hosseini Teherani, Philippe Bove, Michael Molinari, Michel Troyon, Alain Largeteau, Gérard Demazeau, Colin Scott, Gaelle Orsal, Henri-Jean Drouhin, Abdallah Ougazzaden, Manijeh Razeghi
Phys. Status Solidi C., 1-5 (2013)-- August 6, 2013 ...[Visit Journal]
Self-forming, vertically-aligned, arrays of black-body-like ZnO moth-eye nanostructures were grown on Si(111), c-Al2O3, ZnO and high manganese austenitic steel substrates using Pulsed Laser Deposition. X-ray diffraction (XRD) revealed the nanostructures to be well-crystallised wurtzite ZnO with strong preferential c-axis crystallographic orientation along the growth direction for all the substrates. Cathodoluminescence (CL) studies revealed emission characteristic of the ZnO near band edge for all substrates. Such moth-eye nanostructures have a graded effective refractive index and exhibit black-body characteristics. Coatings with these features may offer improvements in photovoltaic and LED performance. Moreover, since ZnO nanostructures can be grown readily on a wide range of substrates it is suggested that such an approach could facilitate growth of GaN-based devices on mismatched and/or technologically important substrates, which may have been inaccessible till present. [reprint (PDF)]
 
14.  High-power laser diodes based on InGaAsP alloys
M. Razeghi
Nature, Vol.369, p.631-633-- June 23, 1994 ...[Visit Journal]
HIGH-POWER, high-coherence solid-state lasers, based on dielectric materials such as ruby or Nd:YAG (yttrium aluminium garnet), have many civilian and military applications. The active media in these lasers are insulating, and must therefore be excited (or ‘pumped’) by optical, rather than electrical, means. Conventional gas-discharge lamps can be used as the pumping source, but semiconductor diode lasers are more efficient, as their wavelength can be tailored to match the absorption properties of the lasing material. Semiconducting AlGaAs alloys are widely used for this purpose, but oxidation of the aluminium and the spreading of defects during device operation limit the lifetime of the diodes3, and hence the reliability of the system as a whole. Aluminium-free InGaAsP compounds, on the other hand, do not have these lifetime-limiting properties. We report here the fabrication of high-power lasers based on InGaAsP (lattice-matched to GaAs substrates), which operate over the same wavelength range as conventional AlGaAs laser diodes and show significantly improved reliability. The other optical and electrical properties of these diodes are either comparable or superior to those of the AlGaAs system. [reprint (PDF)]
 
14.  Extended electrical tuning of quantum cascade lasers with digital concatenated gratings
S. Slivken, N. Bandyopadhyay, Y. Bai, Q. Y. Lu, and M. Razeghi
Appl. Phys. Lett. 103, 231110 (2013)-- December 6, 2013 ...[Visit Journal]
In this report, the sampled grating distributed feedback laser architecture is modified with digital concatenated gratings to partially compensate for the wavelength dependence of optical gain in a standard high efficiency quantum cascade laser core. This allows equalization of laser threshold over a wide wavelength range and demonstration of wide electrical tuning. With only two control currents, a full tuning range of 500 nm (236 cm−1) has been demonstrated. Emission is single mode, with a side mode suppression of >20 dB. [reprint (PDF)]
 
14.  Two‐dimensional electron gases in quantum well and superlattices of Ga0.25In0.75As0.50P0.50/InP heterostructures grown by low pressure metalorganic chemical vapor deposition
M. Razeghi; J. P. Duchemin; J. C. Portal
Appl. Phys. Lett. 46 (1): 46–48 (1985)-- January 1, 1985 ...[Visit Journal]
We report the first observation of a two‐dimensional electron gas from Shubnikov–de Haas experiments, in a Ga0.25In0.75As0.50P0.50‐InP heterojunction, multi‐quantum well, and superlattices grown by metalorganic chemical vapor deposition at reduced pressure. [reprint (PDF)]
 
14.  EPR STUDY OF Mn 2. AROUND THE FERROELASTIC TRANSITION POINT OF Pb3(PO4)2
M. Razeghi, B. Houlier and M. Yuste
M. Razeghi et al. EPR STUDY OF Mn 2. AROUND THE FERROELASTIC TRANSITION POINT OF Pb3(PO4)2, Solid State Communications, Vol. 26, pp. 665-668. -- January 26, 1978 ...[Visit Journal]
The spin Hamiltonian parameters of Mn 2÷ have been measured above and below the transition point (180"C) of the lead phosphate. They show that Mn 2+ substitutes a Pbl ion. Between 175 and 180vC the principal axis OX of the fine tensor is parallel to the wave vector of the soft mode which condensates at the transition point. An exaltation of the linewidth is observed. The linewidth remains constant within 50C of Te; in this temperature range, the "static regime" is achieved, and the correlation time of the fluctuations is less than 10 -s sec. [reprint (PDF)]
 
14.  High-speed, low-noise metal-semiconductor-metal ultraviolet photodetectors based on GaN
D. Walker, E. Monroy, P. Kung, J. Wu, M. Hamilton, F.J. Sanchez, J. Diaz, and M. Razeghi
Applied Physics Letters 74 (5)-- February 1, 1999 ...[Visit Journal]
We present the fabrication and characterization of nonintentionally doped GaN and GaN:Mg Schottky metal–semiconductor–metal (MSM) photodetectors, grown on sapphire by metalorganic chemical vapor deposition. Low-leakage, Schottky contacts were made with Pt/Au. The devices are visible blind, with an ultraviolet/green contrast of about five orders of magnitude. The response times of the MSM devices were <10 ns and about 200 ns for GaN and GaN:Mg, respectively. The noise power spectral density remains below the background level of the system (10−24  A²/Hz) up to 5 V, for the undoped GaN MSM detector. [reprint (PDF)]
 
14.  High-power, room-temperature and continuous-wave operation of distributed-feedback quantum-cascade lasers at λ = 4.8 µm
J.S. Yu, S. Slivken, S.R. Darvish, A. Evans, B. Gokden and M. Razeghi
Applied Physics Letters, 87 (4)-- July 25, 2005 ...[Visit Journal]
The authors present high-power continuous-wave (cw) operation of distributed-feedback quantum-cascade lasers. Continuous-wave output powers of 56 mW at 25 °C and 15 mW at 40 °C are obtained. Single-mode emission near 7.8 µm with a side-mode suppression ratio of >=30 dB and a tuning range of 2.83 cm−1 was obtained between 15 and 40 °C. The device exhibits no beam steering with a full width at half maximum of 27.4° at 25 °C in cw mode. [reprint (PDF)]
 
14.  Intrinsic AlGaN photodetectors for the entire compositional range
D. Walker, X. Zhang, A. Saxler, P. Kung, J. Xu, and M. Razeghi
SPIE Conference, San Jose, CA, -- February 12, 1997 ...[Visit Journal]
AlxGa1-xN ultraviolet photoconductors with cut- off wavelengths from 365 nm to 200 nm have been fabricated and characterized. Various characteristics of the devices, such as photoresponse, voltage-dependent responsivity, frequency-dependent responsivity and noise spectral density, were measured and cross-referenced with optical, electrical and structural characteristics of the material to provide information about the mechanisms taking place during detection. The maximum detectivity reached 5.5 X 108 cm·Hz½/W at a modulating frequency of 14 Hz. The effective majority carrier lifetime in AlxGa1-xN materials, derived from frequency-dependent photoconductivity measurements, has been estimated to be from 6 to 35 msec. The frequency-dependent noise-spectrum shows that it is dominated by Johnson-noise at high frequencies for low Al-composition samples. [reprint (PDF)]
 
14.  High Performance Solar-Blind Ultraviolet Focal Plane Arrays Based on AlGaN
Erdem Cicek, Ryan McClintock, Abbas Haddadi, William A. Gaviria Rojas, and Manijeh Razeghi
IEEE Journal of Quantum Electronics, Vol. 50, Issue 8, p 591-595-- August 1, 2014 ...[Visit Journal]
We report on solar-blind ultraviolet, AlxGa1-x N- based,p-i-n,focal plane array (FPA) with 92% operability. At the peak detection wavelength of 278 nm, 320×256-FP A-pixel showed unbiased peak external quantum efficiency (EQE) and responsivity of 49% and 109 mA/W, respectively, increasing to 66% under 5 volts of reverse bias. Electrical measurements yielded a low-dark current density: <7×10-9A/cm², at FPA operating voltage of 2 volts of reverse bias. [reprint (PDF)]
 
14.  Type-II InAs/GaSb/AlSb superlatticebased heterojunction phototransistors: back to the future
Abbas Haddadi, Arash Dehzangi, Romain Chevallier, Thomas Yang, Manijeh Razeghi
Proc. SPIE 10540, Quantum Sensing and Nano Electronics and Photonics XV- Page-1054004-1-- January 26, 2018 ...[Visit Journal]
Most of reported HPTs in literatures are based on InGaAs compounds that cover NIR spectral region. However, InGaAs compounds provide limited cut-off wavelength tunability. In contrast, type-II superlattices (T2SLs) are a developing new material system with intrinsic advantages such as great flexibility in bandgap engineering, low growth and manufacturing cost, high-uniformity, auger recombination suppression, and high carrier effective mass that are becoming an attractive candidate for infrared detection and imaging from short-wavelength infrared to very long wavelength infrared regime. We present the recent advancements in T2SL-based heterojunction phototransistors in e– SWIR, MWIR and LWIR spectral ranges. A mid-wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb superlattices on GaSb substrate has been demonstrated. Then, we present the effect of vertical scaling on the optical and electrical performance of heterojunction phototransistors, where the performance of devices with different base width was compared as the base was scaled from 60 down to 40 nm. [reprint (PDF)]
 
13.  Investigations on the substrate dependence of the properties in nominally-undoped β-Ga2O3 thin films grown by PLD
F. H. Teherani ; D. J. Rogers ; V. E. Sandana ; P. Bove ; C. Ton-That ; L. L. C. Lem ; E. Chikoidze ; M. Neumann-Spallart ; Y. Dumont ; T. Huynh ; M. R. Phillips ; P. Chapon ; R. McClintock ; M. Razeghi
Proc. SPIE 10105, Oxide-based Materials and Devices VIII, 101051R-OLD-- March 23, 2017 ...[Visit Journal]
Nominally-undoped Ga2O3 layers were deposited on a-, c- and r-plane sapphire substrates using pulsed laser deposition. Conventional x-ray diffraction analysis for films grown on a- and c-plane sapphire showed the layers to be in the β-Ga2O3 phase with preferential orientation of the (-201) axis along the growth direction. Pole figures revealed the film grown on r-plane sapphire to also be in the β-Ga2O3 phase but with epitaxial offsets of 29.5°, 38.5° and 64° from the growth direction for the (-201) axis. Optical transmission spectroscopy indicated that the bandgap was ~5.2eV, for all the layers and that the transparency was > 80% in the visible wavelength range. Four point collinear resistivity and Van der Pauw based Hall measurements revealed the β-Ga2O3 layer on r-plane sapphire to be 4 orders of magnitude more conducting than layers grown on a- and c-plane sapphire under similar conditions. The absolute values of conductivity, carrier mobility and carrier concentration for the β-Ga2O3 layer on r-sapphire (at 20Ω-1.cm-1, 6 cm²/Vs and 1.7 x 1019 cm-3, respectively) all exceeded values found in the literature for nominally-undoped β-Ga2O3 thin films by at least an order of magnitude. Gas discharge optical emission spectroscopy compositional depth profiling for common shallow donor impurities (Cl, F, Si and Sn) did not indicate any discernable increase in their concentrations compared to background levels in the sapphire substrate. It is proposed that the fundamentally anisotropic conductivity in β-Ga2O3 combined with the epitaxial offset of the (-201) axis observed for the layer grown on r-plane sapphire may explain the much larger carrier concentration, electrical conductivity and mobility compared with layers having the (-201) axis aligned along the growth direction. [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.  Hole-initiated multiplication in back-illuminated GaN avalanche photodiodes
R. McClintock, J.L. Pau, K. Minder, C. Bayram, P. Kung and M. Razeghi
Applied Physics Letters, Vol. 90 No. 14, p. 141112-1-- April 2, 2007 ...[Visit Journal]
Avalanche p-i-n photodiodes were fabricated on AlN templates for back illumination. Structures with different intrinsic layer thicknesses were tested. A critical electric field of 2.73 MV/cm was estimated from the variation of the breakdown voltage with thickness. From the device response under back and front illumination and the consequent selective injection of holes and electrons in the junction, ionization coefficients were obtained for GaN. The hole ionization coefficient was found to be higher than the electron ionization coefficient as predicted by theory. Excess multiplication noise factors were also calculated for back and front illumination, and indicated a higher noise contribution for electron injection. [reprint (PDF)]
 
13.  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)]
 

Page 23 of 31:  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 31  >> Next  (769 Items)