摘要:

We have developed low resistance (&rgr;c∼1×10−6&OHgr; cm2) Ge/Pd‐based (the Au/Ge/Pd and the Ag/Ge/Pd contacts) Ohmic contact schemes processed at temperatures 150–175 °C ton‐GaAs (n∼1×1018cm−3). The Ohmic contact formation mechanism can be rationalized in terms of the solid phase regrowth (SPR) principle and the interdiffusion between Au (or Ag) and Ge. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114552

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A new approach for simulating the dynamics of electrons, phonons, and photons is described. The technique provides a Monte Carlo simulation of particle dynamics without the statistical noise associated with direct Monte Carlo simulation, treats physical phenomena with a wide range of time scales, and has a good computational efficiency. A transition matrix is first precomputed by direct Monte Carlo simulation. Particle populations are then updated at regular time steps by simple matrix multiplication while correcting for nonlinear effects such as carrier–carrier scattering, band filling, hot phonons, etc. The technique is well suited to studies of quantum well laser devices and pump‐probe experiments where direct Monte Carlo simulation is exceedingly difficult. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114553

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The first measurements of subpicosecond dynamics of carrier capture and decay in Be &dgr;‐doped GaAs structures withp‐doping density ranging from 6×1012to 2×1014cm−2and spatial distribution on monolayer scale show that photoexcited carriers are captured in the &dgr;‐doped layer in <1 ps. Luminescence decay rates show a strong dependence on energy of the hole in the two‐dimensional Fermi gas. We attribute this to a change in the spatial electron‐hole overlap resulting from band‐mixing effects. We show that Be density fluctuations lead to strong carrier localization. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114554

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Er‐doped GaP layers were deposited on Si (111) substrates using atmospheric pressure metalorganic vapor phase epitaxy. A strong characteristic Er3+intra‐4f‐shell emission at 0.80 eV (1.54 &mgr;m) is observed over the temperature range of 12–300 K. The integrated intensity of the 0.80 eV emission is only weakly temperature dependent, decreasing less than 50% as temperature increases from 12 to 300 K. These results indicate that Er‐doped GaP thin films deposited on Si are suitable as a material for integrated optoelectronic applications. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115174

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Visible luminescence has been obtained from ensembles of defect‐free, InxAl(1−x)As islands of ultrasmall dimensions embedded in AlyGa(1−y)As cladding layers. These structures were grown by molecular beam epitaxy and studied with low‐temperature photoluminescence (PL) and transmission electron microscopy. Visible luminescence is produced using various compositions of InxAl(1−x)As/AlyGa(1−y)As. Quantum dot size distributions, planar densities, dot heights, and wetting layer thicknesses are presented and correlated with the PL spectra. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115175

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Intense photoluminescence (PL) was observed from a new class of Si‐based quantum well structures (QWs), that is, neighboring confinement structure (NCS). NCS consists of a single pair of tensile‐strained‐Si layer and a compressive‐strainedSi1−yGeylayer sandwiched by completely relaxedSi1−xGex(layers.Inspiteoftheindirectbandstructureinrealandkspaces,radiativerecombinationwasenhancedcomparedwithnotonlytype‐IIstrained‐Si/relaxed‐Si1−xGexQWs but also type‐I strained‐Si1−yGey/relaxed‐Si1−xGexQWs. PL without phonon participation was found to dominate the spectrum possibly due to the effective carrier confinement for both electrons and holes. Quantum confinement effect was clearly observed by varying the well width, showing that the expected band alignment is realized. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115176

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The electrical properties of the silicon dioxide/n‐type (100) InP interface were significantly improved by thin interlayers of chemical bath deposited CdS. The CdS layer and CdS/InP interface were investigated with x‐ray photoelectron spectroscopy (XPS) and photoluminescence (PL). XPS data showed reduction of native oxides and the prevention of subsequent substrate oxide growth following CdS layer deposition. PL spectra, measured between 1.0 and 1.3 &mgr;m, indicate a reduction in phosphorus vacancies. Metal–insulator–semiconductor (MIS) capacitors fabricated with CdS‐treated InP substrates displayed interface‐state densities below 1×1011eV−1cm−2when determined from the difference between the high‐ and low‐frequency capacitance data.

ISSN:0003-6951    

DOI:10.1063/1.115177

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The buildup of interface states with high field (HF) stressing have been observed in thermally grown oxide, N2O nitrided oxide (NO), and reoxided nitrided oxide (RNO). The DLTS technique was used to analyze the electronic properties of the Si/SiO2interface. We show that N2O nitridation of SiO2changes the electronic distribution of states at the Si/SiO2interface after HF electrical stress. Our results indicate that this nitrogen plays an important role in preventing the creation of a center atEt1=0.34 eV below the bottom of the conduction band. However, the nitrogen is responsible for a new level atEt2=0.22 eV below the bottom of the conduction band after the NO device is stressed. Also, reoxidation and increasing time of the reoxidation shift the maximum of the peak level away from theEt2towardEt1. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115178

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Photoluminescence of GaN layers grown on 6H–SiC substrates was studied in the temperature range 77–900 K. GaN layers were grown by metalorganic chemical vapor deposition. The temperature dependence of the band gap of GaN was measured throughout the entire temperature range. Edge cavity stimulated emission from photopumped GaN layers was observed in the temperature range 77–450 K. The full width at half‐maximum (FWHM) of the stimulated emission peak was ∼3 nm at 300 K and ∼7 nm at 450 K. Multipass stimulated emission with Fabry–Pe´rot modes was detected from GaN. The FWHM of Fabry–Pe´rot modes was ∼0.2 nm (300 K). ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115179

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A theoretical study of the effects of in‐plane magnetic fields on the interband optical absorption spectra of quasiperiodic GaAs–(Ga,Al)As Fibonacci superlattices is presented within the effective‐mass approximation. The electron‐envelope wave functions and magnetic subbands are obtained by an expansion in harmonic‐oscillator wave functions. The theoretical optical absorption spectra are calculated for magnetic fields related by integer powers of the golden mean &tgr;=(1+&sqrt;5)/2. It is unambiguously shown that, for magnetic‐field values scaled by &tgr;2n, the corresponding optical absorption spectra essentially exhibit a self‐similar behavior, with the width of the peaks increasing linearly with the field, in agreement with the experimental results by D. Toet, M. Potemski, Y. Y. Wang, J. C. Maan, L. Tapter, and K. Ploog [Phys. Rev. Lett.66, 2128 (1991)]. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115180

出版商:AIP    

年代:1995

数据来源: AIP