摘要:

The application of the ion‐beam technique to the nitriding of steels is described. Preliminary results indicate that the technique can be successfully applied for this purpose. Some of the structural changes obtained by this technique are similar to those obtained by ion nitriding. The main difference is the absence of the compound layer and the iron nitrides diffraction lines. The dependence of the resultant microhardness on beam voltage for super nitralloy was found to be different from that of 304 stainless steel.

ISSN:0021-8979    

DOI:10.1063/1.334534

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Electron paramagnetic resonance spectra of fast neutron irradiated semi‐insulating GaAs, recorded at 9 GHz and 4.2 K, have been studied as a function of isochronal thermal anneals. Their decomposition into quadruplet and singlet allows one to determine the main annealing temperatures of the corresponding defects, previously identified as As4+Gaand V2−Ga, which occur respectively at 400 and 600 °C. Comparison with the behavior of implantation damage shows that electrical activation of Be+implants is correlated with the annealing of the main defects on the cation sublattice. Finally, the linewidth variation of the quadruplet during its decay indicates a concomitant change of the local environment of the As4+Gacenter.

ISSN:0021-8979    

DOI:10.1063/1.334535

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

We have studied the sputtering of chlorinated Si surfaces by 1‐keV Ne+impact using secondary ion mass spectrometry and low‐energy ion scattering spectroscopy. Under steady‐state conditions of submonolayer Cl coverage, SiCl+xions (x=0–3) are all observed with identical coverage dependence. Cross sections for removal of Cl from Si are independent of initial coverage in the submonolayer regime. Sputter cross sections increase from 0.5×10−15cm2at normal incidence to a maximum of 22×10−15cm2at ∼70° angle of incidence. Secondary ion yields are shown to be markedly dependent on the presence of recoil‐implanted Cl in the substrate. The details of Cl sputtering and Si removal processes in ion‐assisted etching suggest a major role for recoil implantation of Cl into the Si lattice in formation and removal of SiClxproducts in etching reactions.

ISSN:0021-8979    

DOI:10.1063/1.334536

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Integrated circuit technology has been successfully applied to the design and fabrication of 0.5×0.5‐cm planar multijunction solar‐cell chips. Each of these solar cells consisted of six voltage‐generating unit cells monolithically connected in series and fabricated on a 75‐&mgr;m‐thick,p‐type, single crystal, silicon substrate. A contact photolithic process employing five photomask levels together with a standard microelectronics batch‐processing technique were used to construct the solar‐cell chip. The open‐circuit voltage increased rapidly with increasing illumination up to 5 AM1 suns where it began to saturate at the sum of the individual unit‐cell voltages at a maximum of 3.0 V. A short‐circuit current density per unit cell of 240 mA/cm2was observed at 10 AM1 suns.

ISSN:0021-8979    

DOI:10.1063/1.334537

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The operation of a photovoltaic solar cell is discussed with a quantum two‐level system as a model. A detailed‐balance calculation is carried out, from which the parameters of the converter, illuminated by radiation from a black body, are exactly obtained in different geometries, taking into account radiative recombination processes. It is shown that in a 4&pgr; geometry (source fully surrounding the converter) with total radiative recombination, the thermodynamic efficiency is equal to the Carnot efficiency at zero current (open circuit): the converter behaves as an ideal thermal engine, fully reversible when delivering no power (the practical efficiency is evidently zero). The reversibility is ensured by the complete exchange of photons between the source and the converter. The current‐voltage relation is obtained in all cases, and it is shown that the two‐level system follows the ideal diode equation. The calculation of the thermodynamic efficiency is generalized to an energy band system (real semiconductor) with radiative recombination and is shown to be maximum at open circuit, but lower than the Carnot efficiency because of irreversibilities induced by the thermalization of carriers. The effective source temperature concept is discussed. It is shown to be valid for a two‐level system, but has less physical meaning for a two‐band system.

ISSN:0021-8979    

DOI:10.1063/1.334486

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Detailed description is given of the structure, operation, fabrication, and performance of the novel, fast‐response silicon liquid‐crystal spatial light modulator. Applications for large screen displays and optical data processing are described.

ISSN:0021-8979    

DOI:10.1063/1.334487

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The concentric circle pattern of growth striations in Czochralski (CZ) silicon wafer has been found to cause the fixed pattern noise in the reproduced image by solid‐state imagers with thep‐well structure. The microgrowth striations of dopant impurities in 4‐in.n‐type CZ silicon wafers have been examined in terms of noise video signals ofp‐well Charge Priming Device imagers. Striation periods as narrow as 10 &mgr;m can be revealed, which may be overlooked by the conventional spreading resistance method.

ISSN:0021-8979    

DOI:10.1063/1.334488

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A unified theory of electron transport in a phonon bath using the Wigner formalism is presented. The resulting quantum kinetic equation not only lends itself to a phase space description of the electron transport, but also includes higher‐order effects such as degeneracy, collisional broadening, and intracollisional field effect. The equation provides a rigorous theoretical foundation for Monte Carlo simulation of high‐field electron transport in submicron and quasi‐two‐dimensional device structures.

ISSN:0021-8979    

DOI:10.1063/1.334489

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Detailed analysis of x‐ray rocking curves was used to determine the depth profile of strain and composition in a 2500‐A˚‐thick layer of AlxGa1−xAs grown by metalorganic chemical vapor deposition on ⟨100⟩ GaAs. Thexvalue and layer thickness were in good agreement with the values expected from growth parameters. The presence of a transition region, 280 A˚ thick, was detected by the rocking curve. In this region, the Al concentration varies smoothly from 0 to 0.87. Measurement and control of the sharpness of such interfaces has important implications for heterojunction devices.

ISSN:0021-8979    

DOI:10.1063/1.334490

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

AlxGayIn1−x−yP withx+y=0.51, lattice matched to the GaAs substrate, has been grown by organometallic vapor phase epitaxy. The simple, horizontal, IR heated system operates at atmospheric pressure using the reactants TMAl, TMGa, TMIn, PH3, and H2. Alloys giving room temperature, band edge photoluminescence (PL) have been grown in the temperature range 625–780 °C. Emission wavelengths as short as 5820 A˚ (2.13 eV) are reported. High growth temperatures are found to give layers with the best surface morphology and PL intensity. The use of high temperatures is especially important for high Al content alloys. PL atx=0.2 is obtained only for temperatures above 740 °C.

ISSN:0021-8979    

DOI:10.1063/1.334491

出版商:AIP    

年代:1985

数据来源: AIP