摘要:

Deep levels have been examined in nonintentionally dopedp‐type gallium selenide single crystals using photoinduced current transient spectroscopy measurements. Two hole trapping levels at 0.20 and 0.80 eV above the valence band have been observed and the corresponding thermal capture cross section evaluated. The possible origin and nature of these centers are also discussed.

ISSN:0021-8979    

DOI:10.1063/1.345090

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The gain of an electromagnetic wave in a free electron laser is calculated. It is demonstrated that when the electron beam develops instabilities, this gain can be enhanced. Calculations for the case of the two‐stream instability show that the growth rate is more than seven times larger and the gain per pass can be increased by more than two orders of magnitudes.

ISSN:0021-8979    

DOI:10.1063/1.345091

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Interfacial reactions between thin films of Al and amorphous (a‐) SiC annealed with tungsten‐halogen lamps lead to the formation of Si fractal‐like structures at temperatures as low as 275 °C in less than 100 s. By usinga‐SiC/Al/a‐SiC sandwiches with different SiC/Al thickness ratios, it is shown that the nucleation of Si crystals is faster on smaller‐grained Al. This is attributed to the higher Al surface energy and the increased density of high‐energy multiple grain junctions in thinner (smaller grained) Al layers. When the Al layer is very thin (≤50 A˚) a solid‐state amorphization reaction occurs between Al anda‐SiC without subsequent Si crystallization. Formation of Al4C3follows Si crystallization, or in the very thin Al layer, the amorphization reaction.

ISSN:0021-8979    

DOI:10.1063/1.345092

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The outdiffusion of Be implanted into GaAs has been found to be identical after capless or capped (Si3N4or SiO2) rapid thermal annealing (RTA) at 900–1000 °C and to depend on the Be dose and its proximity to the surface. The outdiffusion is more pronounced when the Be implant is shallow (<0.1 &mgr;m) and/or the Be+dose is high (>1×1015cm−2). It is demonstrated that the Be outdiffusion is driven by the presence of a highly damaged surface layer. Auger results suggest the formation of a BeOxcompound at the surface of a high‐dose (1×1016cm−2) Be‐implanted sample that underwent capless RTA at 1000 °C/1 s. It appears that BeOxformation occurs when the outdiffused Be interacts with the native Ga/As oxides during annealing. All the Be remaining in the GaAs after a >900 °C/2 s RTA is electrically active.

ISSN:0021-8979    

DOI:10.1063/1.345093

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A decrease of Raman conversion efficiency pumped by KrF excimer laser at high repetition rate was observed in a sealed hydrogen Raman cell. A hydrogen gas circulating system was designed with gas pressure up to 50 atm; it can be operated at a high repetition rate without decrease of Raman conversion efficiency.

ISSN:0021-8979    

DOI:10.1063/1.346080

出版商:AIP    

年代:1990

数据来源: AIP