摘要:

The backscattering from and the implantation of 0.5–10‐keV hydrogen and helium in Au is investigated with the MARLOWE and TRIM computer codes. The following are found in this paper: (1) The results of the MARLOWE and the much faster TRIM codes are in satisfactory agreement. (2) The influence of potential parameters and energy loss models (LSS and Oen‐Robinson) is mainly on the heights and to less extent on the shapes of the energy distributions of backscattered particles. (3) The experimental data from the preceding paper favor the use of a potential for the calculation, which is weaker than the Molie`re potential. This can be simulated by using a screening length smaller than the Firsov value.

ISSN:0021-8979    

DOI:10.1063/1.327687

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Thermionic emission patterns from the single‐crystal LaB6[100], [110], [111], and [210] tips have been observed under the Schottky condition. The observed emission patterns are interpreted on the basis of a model involving an anisotropic work function of LaB6; the regions around the [111] crystal orientation have a high‐work function, while those around the [210] crystal orientation have a low work function. This model also explains qualitatively the order of the total emission currents from those tips. The observed patterns predominantly consist of the emission from the conical face rather than the top of the tips under this experimental condition. Changes in the emission pattern and cathode surface in operation at 10−4Torr are also discussed.

ISSN:0021-8979    

DOI:10.1063/1.327688

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Thermomigration of Al‐rich liquid zones through Si is used to join single‐crystalline Si wafers and also to recrystallize polycrystalline Si into single‐crystalline material. Several possible applications of this technique are discussed.

ISSN:0021-8979    

DOI:10.1063/1.327689

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

We examine the properties of solutions to the sine‐Gordon equation in the presence of various boundary conditions. Reflection from the boundary of a semi‐infinite system with a fixed or free endpoint is found to be explainable in terms of the standard soliton‐soliton and soliton‐antisoliton solutions, respectively, for the infinite system. We also consider both nonlinear standing‐wave and solitonic solutions to the sine‐Gordon equation on a system of finite lengthL. Through the use of the application by Costabileetal. of the separation of variables ansatz due to Lamb, analytic expressions in terms of Jacobi elliptic functions are found for these two types of solutions, which assume the forms appropriate to the infinite and semi‐infinite system, respectively, asL→∞. Concentrating on the solitonic solution, we examine its symmetry properties, relations among its characteristic parameters, and give plots of its waveform in several cases. The effect of the boundaries on this solution is such that the oscillation of the soliton center closely resembles that of a particle in a symmetric potential, whose shape is determined straightforwardly from the time dependence of the soliton position and of the potential energy of the system.

ISSN:0021-8979    

DOI:10.1063/1.327690

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Degradation mechanisms of GaAs0.9P0.1light‐emitting diodes for optical fiber communication systems were studied to elucidate the effects of internal compressive stress (on the order of 107–108dyn/cm2) on initial rapid degradation. The diodes were fabricated from wafers with various phosphorus composition gradients (?0.7%/&mgr;m) in the tapered layer.Experimental results from the degradation of the diodes operating at 660 A/cm2showed that the lifetimes of the diodes increased with decreasing the compositional grading in the crystals. The improved lifetime is due not only to the suppression of ⟨110⟩ dark‐line defects but also to the slow growth velocities of ⟨100⟩ dark‐line defects and due to slow accumulation rates of nonradiative recombination centers near the PN junctions at low internal stress. For the first time, the growth velocities of ⟨100⟩ dark‐line defects during initial rapid degradation were observed to depend on the internal compressive stress.

ISSN:0021-8979    

DOI:10.1063/1.327691

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

It is shown that photoselection and rotational diffusion should be considered in transient‐gain experiments. Modified theoretical expressions are given which describe the time dependence of gain signals for polarized beams.

ISSN:0021-8979    

DOI:10.1063/1.327692

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The interaction between an implanted layer in silicon and a surface acoustic wave (SAW) traveling on a neighboring piezoelectric was studied, and the resulting transverse acoustoelectric voltage has been found to be an effective indicator of the activation of the implanted species in the silicon lattice obtained during annealing treatments following ion implantation. The method can be used to monitor an entire wafer and is nondestructive.

ISSN:0021-8979    

DOI:10.1063/1.327693

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The shock waves induced in the surrounding atmosphere by an air plasma were investigated by laser interferometry. The air‐breakdown plasma was produced by a TEA‐CO2laser in front of a solid target. The results were compared to the predictions of the theory of intense explosions in gases and a good agreement was inferred. It was also determined that the symmetry of the expansion of the initial shock wave is determined by the plasma‐source shape and, accordingly, depends on the laser power density incident on the target surface. However, for further stages all the shock waves expand spherically.

ISSN:0021-8979    

DOI:10.1063/1.327694

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A mechanically polished brilliant surface of diamond differed from the amorphous Beilby layer as formed at solid surfaces in general. A RHEED pattern observed from the former surface was characteristic enough to demonstrate that RHEED served as a nondestructive testing means for identifying diamond.

ISSN:0021-8979    

DOI:10.1063/1.327695

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Heavily Ni‐doped magnesium oxide crystals, grown by the arc‐fusion technique, have been investigated using optical and transmission electron microscopy to examine the dislocation content, sub‐boundaries, and impurity precipitates. Yield stress measurements were also made. Dislocation structures and impurity precipitates at the sub‐boundaries are described, and their implications concerning the use of these crystals as laser materials are discussed.

ISSN:0021-8979    

DOI:10.1063/1.327696

出版商:AIP    

年代:1980

数据来源: AIP