APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

7 Aug 2000

Volume 77, Issue 6, pp. 767-915

Return to All Sections
back to top
RSS Feeds

Nonequilibrium electron distributions in a three-subband InGaAs/InAlAs quantum well studied via double resonance spectroscopy

G. B. Serapiglia, K. L. Vodopyanov, and C. C. Phillips

Appl. Phys. Lett. 77, 857 (2000); http://dx.doi.org/10.1063/1.1306651 (3 pages) | Cited 5 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Midinfrared optical pumping of electrons from the ground (n = 1) to the first excited (n = 2) subband of the quantum well produces a strongly nonthermal electron distribution which is probed spectroscopically. Two sharp induced absorption peaks appear, associated with electrons which have scattered from the upper subband via longitudinal optical (LO) phonon emission and absorption. The presence of the phonon absorption channel evidences the importance of nonequilibrium LO phonon populations (nph ∼ 1), and the impact on the nonradiative intersubband scattering rates in quantum cascade laser devices is explored. © 2000 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
73.61.Ey III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
71.38.-k Polarons and electron-phonon interactions
72.40.+w Photoconduction and photovoltaic effects
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Thermoelectric figure-of-merit barrier at minimum lattice thermal conductivity?

Gao Min and D. M. Rowe

Appl. Phys. Lett. 77, 860 (2000); http://dx.doi.org/10.1063/1.1306652 (3 pages) | Cited 12 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An analysis of the transport properties data on established thermoelectric materials indicates that the ratio of the electrical power factor to optimum electrical conductivity appears constant. This result, when combined with the previously proposed concept of a minimum thermal conductivity, enables realistic maximum dimensionless figures-of-merit to be calculated. It is concluded that a barrier to increasing the dimensionless figure-of-merit appears to exist which is around 2 at room temperature and that overcoming this barrier will require the development of materials with radically different transport properties from those currently available. © 2000 American Institute of Physics.
Show PACS
72.20.Pa Thermoelectric and thermomagnetic effects
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
72.10.-d Theory of electronic transport; scattering mechanisms

SiO2-passivated lateral-geometry GaN transparent Schottky-barrier detectors

V. Adivarahan, G. Simin, J. W. Yang, A. Lunev, M. Asif Khan, N. Pala, M. Shur, and R. Gaska

Appl. Phys. Lett. 77, 863 (2000); http://dx.doi.org/10.1063/1.1306647 (3 pages) | Cited 49 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on a transparent Schottky-barrier ultraviolet detector on GaN layers over sapphire substrates. Using SiO2 surface passivation, reverse leakage currents were reduced to a value as low as 1 pA at 5 V reverse bias for 200 μm diameter device. The device exhibits a high internal gain, about 50, at low forward biases. The response time (about 15 ns) is RC limited, even in the internal gain regime. A record low level of the noise spectral density, 5×10−23 A2/Hz, was measured at 10 Hz. We attribute this low noise level to the reduced reverse leakage current. © 2000 American Institute of Physics.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
81.65.Rv Passivation
85.60.Dw Photodiodes; phototransistors; photoresistors
73.30.+y Surface double layers, Schottky barriers, and work functions

Effect of oxidation method and post-oxidation annealing on interface properties of metal–oxide–semiconductor structures formed on n-type 4H-SiC C(000math) face

K. Fukuda, W. J. Cho, K. Arai, S. Suzuki, J. Senzaki, and T. Tanaka

Appl. Phys. Lett. 77, 866 (2000); http://dx.doi.org/10.1063/1.1306649 (3 pages) | Cited 16 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The C(000math) face of silicon carbide (SiC) has superior properties such as a faster oxidation ratio and a smoother surface compared with the Si(0001) face. We have investigated the oxidation and post-oxidation annealing effects on the capacitance–voltage and the interface state density (Dit) of n-type SiC metal–oxide–semiconductor (MOS) structures formed on the C(000math) face. It was found that pyrogenic oxidation and hydrogen annealing above 700 °C reduced Dit near the conduction-band edge. The value of Dit at Ec−E = 0.2 eV is 1×1012 eV−1 cm−2, which is comparable with that of the MOS structure formed on the Si(0001) face. However, the value of Dit around the deep level at Ec−E = 0.6 eV is one order of magnitude higher than that of n-type MOS structures formed on the Si(0001) face. It is very important to reduce Dit at the deep level for a high-quality SiO2/SiC interface on the 4H-SiC C(000math) face. © 2000 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
81.65.Mq Oxidation
61.72.Cc Kinetics of defect formation and annealing
81.05.Hd Other semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Metamorphic InP/InGaAs double-heterojunction bipolar transistors on GaAs grown by molecular-beam epitaxy

H. Q. Zheng, K. Radhakrishnan, H. Wang, K. H. Yuan, S. F. Yoon, and G. I. Ng

Appl. Phys. Lett. 77, 869 (2000); http://dx.doi.org/10.1063/1.1306657 (3 pages) | Cited 16 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
InP/InGaAs double-heterojunction bipolar transistor (HBT) structures were grown metamorphically on GaAs substrates by solid-source molecular-beam epitaxy. A linearly graded InxGa1−xP (x varying from 0.48 to 1) buffer layer was used to accommodate the strain relaxation. The crystallinity of the buffer layer and the HBT structure was examined by x-ray diffractometry. Devices with 5×5 μm2 emitter area showed a typical peak current gain of 40, a common-emitter breakdown voltage (BVCEO) higher than 9 V, a current gain cut-off frequency (fT) of 46 GHz, and a maximum oscillation frequency (fmax) of 40 GHz. © 2000 American Institute of Physics.
Show PACS
85.30.Pq Bipolar transistors
84.40.-x Radiowave and microwave (including millimeter wave) technology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties

Room-temperature InAs0.89Sb0.11 photodetectors for CO detection at 4.6 μm

H. H. Gao, A. Krier, and V. V. Sherstnev

Appl. Phys. Lett. 77, 872 (2000); http://dx.doi.org/10.1063/1.1306656 (3 pages) | Cited 20 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An InAs0.89Sb0.11 photovoltaic detector that operates at room temperature in the 2.5–5 μm mid-infrared wavelength region is reported. The photodiode has an extended spectral response compared with other currently available III–V room-temperature detectors. In order to accommodate the large lattice mismatch between the InAs0.89Sb0.11 active region and the InAs substrate, a buffer layer with an intermediate composition was introduced into the structure. In this way, we obtained room-temperature photodiodes with a cutoff wavelength near 5 μm, a peak responsivity of 0.8 A/W, and a detectivity of 1.26×109 cm Hz1/2/W. These devices could be effectively used as the basis of an optical sensor for the environmental monitoring of carbon monoxide at 4.6 μm, or as a replacement for PbSe photoconductors. © 2000 American Institute of Physics.
Show PACS
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Dw Photodiodes; phototransistors; photoresistors
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)

Electron beam-induced increase of electron diffusion length in p-type GaN and AlGaN/GaN superlattices

Leonid Chernyak, Andrei Osinsky, Vladimir Fuflyigin, and E. F. Schubert

Appl. Phys. Lett. 77, 875 (2000); http://dx.doi.org/10.1063/1.1306910 (3 pages) | Cited 24 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The diffusion length, L, of electrons in Mg-doped p-GaN grown by metal-organic chemical vapor deposition was found to increase linearly from 0.55 to 2.0 μm during 1500 s of electron beam irradiation. Similar trends were observed for p-type Mg-doped GaN and AlGaN/GaN superlattices grown by molecular-beam epitaxy. While the electron diffusion length in p-(Al)GaN depends on irradiation time, the diffusion length of holes in n-GaN remains unchanged, with L ∼ 0.35 μm. We attribute the observed diffusion length change in p-(Al)GaN to an increase in the minority carrier lifetime. This increase is likely due to electron beam-induced charging of the deep metastable centers associated with Mg doping. The concentration of these centers was estimated to be ∼ 1018 cm−3. The minority carrier diffusion length increase in p-(Al)GaN, which occurs during electron injection, may lead to self-improvement of the bipolar transistor characteristics. © 2000 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
61.82.Fk Semiconductors
71.55.Eq III-V semiconductors
81.05.Ea III-V semiconductors
73.20.Hb Impurity and defect levels; energy states of adsorbed species
61.80.Fe Electron and positron radiation effects

Sulfur: A potential donor in diamond

D. Saada, Joan Adler, and R. Kalish

Appl. Phys. Lett. 77, 878 (2000); http://dx.doi.org/10.1063/1.1306914 (2 pages) | Cited 48 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We performed first-principle calculations of substitutional sulfur in diamond, in the neutral (S0) and charged states. The energy levels induced by sulfur in diamond are calculated to be 0.15 and 0.5 eV from the bottom of the conduction band, for S0 and the singly ionized state S+, respectively. The formation energy for the neutral state of sulfur is found to be 7.2 eV, lower than that of phosphorus in diamond. The most likely state of sulfur in diamond is found to be the doubly ionized state S++, which cannot act as a donor. However, a small fraction of sulfur can be found in the singly ionized state S+, which can donate an electron for conduction at reasonable temperatures. © 2000 American Institute of Physics.
Show PACS
71.55.Cn Elemental semiconductors
71.20.Mq Elemental semiconductors
81.05.ub Fullerenes and related materials
81.05.Cy Elemental semiconductors

Pyramidal defects in metalorganic vapor phase epitaxial Mg doped GaN

P. Vennéguès, M. Benaissa, B. Beaumont, E. Feltin, P. De Mierry, S. Dalmasso, M. Leroux, and P. Gibart

Appl. Phys. Lett. 77, 880 (2000); http://dx.doi.org/10.1063/1.1306421 (3 pages) | Cited 53 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A transmission electron microscopy study of structural defects induced by the introduction of Mg during the growth of metalorganic vapor phase epitaxy GaN is presented. These defects are assumed to be pyramidal inversion domains with an hexagonal base and {11math3} inclined facets. The tip of the pyramids is always pointing toward the [000math] direction, i.e., in a Ga-terminated film, toward the substrate and in a N-terminated film, toward the surface. A chemical quantitative analysis shows that these pyramidal defects are Mg rich. They are present in all the studied films, independent of the doping level. © 2000 American Institute of Physics.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.-y Defects and impurities in crystals; microstructure
81.05.Ea III-V semiconductors
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close