摘要:

Low‐energy zinc ions have been incorporated in growing MBE GaAs layers producing heavily dopedp‐type material. As‐grown layers retain a substantial amount of radiation damage as indicated by the absence of photoluminescence and low hole mobilities. A postgrowth anneal yields layers with low‐temperature luminescence and mobilities comparable to zinc doped LPE epitaxial layers. Annealed layer quality does not depend on substrate growth temperature or ion energy over the ranges 580–650 °C and 100–3000 eV, respectively. The measured zinc ion sticking coefficient has a value of ∼50% and depends only weakly on ion energy. The data suggest that the sticking coefficients are enhanced by a simple ion burial mechanism and not by an electrostatic attraction between the ion and surface atoms.

ISSN:0003-6951    

DOI:10.1063/1.91007

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

It is shown that Ga1−xAlxAs visible lasers degrade faster at shorter lasing wavelengths. The degradation in the wavelength region below 730 nm can mainly be attributed to the rapid formation of macroscopic defects in the active region. A notable improvement in life is obtained for these shorter wavelength lasers by Te‐doping of the active layer. On the other hand, degradation at above 740‐nm results from enhanced facet oxidation due to high AlAs mole fractions in the layers. Facet coatings using SiO2films effectively suppress facet oxidation. As a result, room‐temperature extrapolated lives exceeding 10 000 h are achieved in the wavelength region above 740 nm.

ISSN:0003-6951    

DOI:10.1063/1.91008

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The efficiency of transparent type MIS solar cells is often below the theoretical estimate due to the simultaneous requirement that the thin metal film have good transparency and high conductivity. In this letter we report the properties of ZnO on Ti as a combined transparent conducting (TC) layer which can be used to reduce the sheet resistance of the thin metal layer.

ISSN:0003-6951    

DOI:10.1063/1.91009

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The capture cross sections and density‐energy distribution of the trap states at the interface between GaAs epitaxial layers and oxide films grown by anodization in oxygen plasma have been determined by deep‐level transient spectroscopy (DLTS). The capture cross sections are of the order of 10−12–10−13cm2. The state density in the energy space range from 1×1013to 3×1013cm−2 eV−1. It has a peak 0.43 eV below the conduction band edge, but increases again near the valence band edge. The existence of traps in the oxide is also suggested. The activation energies of the emission rates determined by constant‐capacitance DLTS with a small pulse voltage are in good agreement with the surface potentials, and no particular band structure at the interface, such as an interface band, has been found.

ISSN:0003-6951    

DOI:10.1063/1.91010

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We have measured the photoluminescence properties of laser‐annealed single‐crystal GaAs. The quantum efficiency of the band‐edge emission at liquid helium temperatures was increased by 3 orders of magnitude after a single 10−3‐s pulse of ruby laser light. This increase in radiative efficiency is thought to be due to dissociation of Si‐donor‐Ga‐vacancy complexes, which is expected to decrease nonradiative processes and possibly increase radiative centers. A theoretical prediction of the temperature distribution at the end of the laser pulse was performed.

ISSN:0003-6951    

DOI:10.1063/1.91011

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Ion‐implanted crystalline silicon annealed in atomic hydrogen photoluminesces at 0.99±0.01 eV in a band having a spectral width of 0.1 eV FWHM. The emitted spectrum does not depend on the chemical nature of the implanted ion (Al, As, D, F, H, Ne, P, Si); however, when the surface is amorphized, a spectrum characteristic of hydrogenated amorphous Si is obtained.

ISSN:0003-6951    

DOI:10.1063/1.91012

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The semiconductor‐semimetal transition in InAs‐GaSb superlattices is observed at a layer thickness in the vicinity of 100 A˚. The transition manifests itself in an increase in the measured carrier concentration as a result of electron transfer from GaSb to InAs when ground subbands of electrons and heavy holes cross each other. Shubnikov‐de Haas measurements confirm the carrier enhancement in the semimetallic state.

ISSN:0003-6951    

DOI:10.1063/1.91013

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The elementary theories of flicker noise in MOSFET’s operating at low drain bias evaluate the spectrumSVeq8f) of the equivalent gate noise emf &dgr;Vequnder the assumptions of an effective mobility &mgr;effthat is independent of the gate voltageVgand of a carrier number in the channel that varies linearly with the gate voltage. We show here that this introduces an errorI2d/[g2m(Vg—VT)2] in the calculated results. Experiments show that this error can be significant, so that it makes some existing interpretations ofSVeq(f) doubtful. The error comes about because at a given drain currentIdthe transconductancegmfor largeVg−VTis smaller than the elementary theory predicts. This affects most MOSFET modeling at low drain bias.

ISSN:0003-6951    

DOI:10.1063/1.91014

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Powder metallurgy is used as an alternative process to produce Nb3Sn and V3Ga composite superconductors with large critical transport currents in magnetic fields above 15T. Whereas for a Cu–30 wt.%Nb +Sn composite the overall current densityJcamounts to 1.0×108A/m2at 16T, values in excess of 4×108A/m2(16 T) are observed for Cu–30 wt.% V+Ga composites.

ISSN:0003-6951    

DOI:10.1063/1.91015

出版商:AIP    

年代:1979

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.91273

出版商:AIP    

年代:1979

数据来源: AIP