摘要:

Large anisotropy in minority carrier diffusion length and specific conductivity is observed in epitaxial layers ofGaInP2alloys withCuPtB-type ordering. Both the diffusion length and specific conductivity are enhanced, by factor of 10, in the [110] direction, parallel to the line of intersection of the ordered (1–11) and(−111)planes with the (001) growth surface. The reduction in transport length in the [1–10] direction is attributed to carrier scattering at domain boundaries. No transport anisotropy is observed in disorderedGaInP2epitaxial layers. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118864

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We present a method to calculate the Hall scattering factor using a Monte Carlo technique. The greater accuracy of the new method makes it possible to calculaterHinp-Si and Ge at room temperature much faster. The models employed in the calculation include all details of the valence band and acoustical and optical phonon scattering processes. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118892

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The electroluminescence behavior of erbium-oxygen-doped silicon light emitting diodes grown by molecular beam epitaxy was studied for a fixed oxygen to erbium concentration ratio of about six. The diodes were operated in reverse bias. An increase of the erbium and oxygen content leads to a stronger erbium intensity at 5 K up to an erbium concentration of1.5×1020 cm−3,an enhanced decrease of the erbium intensity with higher temperatures, and a shift of the temperature quenching onset to lower temperatures. The strongest erbium electroluminescence emission in reverse bias in this set of samples was obtained from annealed Si:Er-diodes doped with concentrations of5×1019,or1.5×1020 cm−3erbium and3×1020or3×1021 cm−3oxygen, respectively. Electroluminescence emission due to erbium was detected up to 440 K. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118893

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

This article deals with a plan view and cross section transmission electron microscopy study of columnar defects in GaN films epitaxially grown on sapphire (0001). They are identified as open-core (0001) Burgers vector dislocations. Their behavior along the film thickness is described: it alternates from open core sections (nanopipes) to closed core sections. This alternating behavior is observed in the first 0.5 &mgr;m close to the interface with sapphire. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118894

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Porous silicon was recently shown to give rise to the same semimetallic Si-III (BC-8) phase as silicon upon application and release of high pressure. This phase is known to have a direct gap and we examine the effect of quantum confinement on its electronic structure. This is performed by combining empirical tight binding andab initiolocal density calculations. The blue shift is found to be similar to what is obtained for nanocrystallites with the diamond structure and the radiative recombination rate is much larger. Comparison with experiment shows that the observed luminescence is not consistent with the quantum confinement hypothesis. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118895

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have demonstrated a 20 period dislocation-free InGaAs/GaAs quantum dot superlattice which is self-formed by the strain from the superlattice taken as a whole rather than by the strain from the strained single layer. The island formation does not take place while growing the corresponding strained single layer. From the variation of the average dot height in each layer, the strain distribution and relaxation process in the capped superlattice have been examined. It is found that the strain is not uniformly distributed and the greatest strains occur at two interfaces between the superlattice and the substrate and the cap layer in the capped superlattice. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118896

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Three important processes dominate the wet thermal oxidation ofAlxGa1−xAson GaAs: (1) oxidation of Al and Ga in theAlxGa1−xAsalloy to form an amorphous oxide, (2) formation and elimination of crystalline and amorphous elemental As and of amorphousAs2O3,and (3) crystallization of the amorphous oxide film. Residual As can lead to strong Fermi-level pinning at the oxidized AlGaAs/GaAs interface, up to a 100-fold increase in leakage current, and a 30&percent; increase in the dielectric constant of the oxide layer. Thermodynamically favored interfacial As may impose a fundamental limitation on the use of AlGaAs wet oxidation in metal-insulatorsemiconductor devices in the GaAs material system. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118897

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

It is widely believed that [001]-grown semiconductor superlattices have an isotropic linear optical response in the (001) plane. In this letter, we use simple symmetry arguments to show that introduction of asymmetry in the [001] direction can induce anisotropy in the (001) plane. The latter is calculated for various AlGaAs heterostructures; it is found that the in-plane birefringence can be comparable to the birefringence ofKH2PO4.©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118852

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Planar Si/InGaAs wafer fusedp-i-nphotodetectors were fabricated and measured. They show high internal quantum efficiency, high speed, record low dark current, and no evidence of charge trapping, recombination centers, or a bandgap discontinuity at the heterointerface. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119085

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report the dc and high frequency performance of thin-film InP-based tunneling hot electron transfer amplifiers bonded to a variety of host substrates. The high-frequency device performance is slightly degraded since the InP substrate removal and bonding process for these devices have not yet been optimized. This demonstration represents an important step toward the development of high-frequency, thin-film InP-based electronic devices integrated with conventional Si-based circuit elements. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.118853

出版商:AIP    

年代:1997

数据来源: AIP