The role of hydrogen in semi-insulating INP

Complexes of vacancy at indium site with one to four hydrogen atoms and isolated hydrogen or hydrogen dimer and other infrared absorption lines, tentatively be assigned to hydrogen related defects were investigated by FTIR. Hydrogen cam passivate imperfections, thereby eliminating detrimental electronic states from the energy bandgap. Incorporated hydrogen can introduce extended defects and generate electrically-active defects. Hydrogen also can acts as an actuator for creating of antistructure defects. Isolated hydrogen related defects(e.. H-2*) may play an important role in the conversion of the annealed wafers from semiconducting to the semi-insulating behavior. H-2* may be a deep donor, whose energy level is very near the iron deep acceptor level in the energy gap.

The effect of low temperature GaAs nucleation on the growth of GaN on Silicon (001) during MOVPE process

High quality cubic GaN was grown on Silicon (001) by metalorganic vapor phase epitaxy (MOVPE) using a GaAs nucleation layer grown at low temperature. The influence of various nucleation conditions on the GaN epilayers' quality was investigated. We found that the GaAs nucleation layer grown by atomic layer epitaxy (ALE) could improve the quality of GaN films by depressing the formation of mixed phase. Photoluminescence (PL) and X-ray diffraction were used to characterize the properties of GaN epilayers. High quality GaN epilayers with PL full width at half maximum (FWHM) of 130meV at room temperature and X-ray FWHM of 70 arc-min were obtained by using 10-20nm GaAs nucleation layer grown by ALE.

Influence of open-tube Ga diffusion on the characteristics for thyristor

Open-tube Ga diffusion into a SiO2/Si structure was used for fabrication of the high speed thyristor. The advantages of open-tube Ga diffusion are as follows; it is easier to operate and easier to control the profile of the Ga concentration during processing, a clean surface, which is free from alloy spots can be obtained, this technique ensures to improve the on-state characteristics and dynamic characteristics.

静态存储器单粒子翻转率预示的在轨验证

SRAM型FPGA配置区的单粒子翻转可能对系统的功能产生严重的影响,因此必须进行针对性的加固措施,而加固的重要依据之一是在轨翻转率结果。文章将地面获得的Hitachi 4Mb SRAM HI628512单粒子翻转率预示结果与搭载在极轨卫星SAC-C等上的飞行试验的结果进行了比较。分析表明基于国内地面试验数据和FOM方法预示的在轨翻转率与国外的在轨监测数据接近,多位翻转的试验结果也得到了在轨试验数据的验证。这些结果表明我国在单粒子翻转的模拟试验技术和在轨翻转率预示方面取得了相当的进展,可以为卫星电子系统抗辐射加固设计提供有力的保障。

用于热核巨共振研究的大面积BGO闪烁探测器

报道了大面积 BGO闪烁探测器用于 132 Me V16O+ 197Au反应中形成的热核巨共振研究 ,利用飞行时间法鉴别中子、γ。用 EGS4程序模拟探测器对 γ连续谱的响应 ,利用 BGO闪烁探测器中 Ge俘获中子发射的 γ对探测器进行能量刻度。

Enhanced photoluminescence of Ar+ implanted sapphire before and after annealing

In this paper, we studied the changes in the photoluminescence spectra of the Ar+ ion implanted monocrystalline sapphire annealed at different atmospheres and different temperatures. Single crystals of sapphire (Al2O3) with the (1 0 (1) over bar 0) (m-samples) orientation were implanted at 623 K with 110 keV Ar+ ions to a fluence of 9.5 x 10(16) ions/cm(2). Photoluminescence measurement of the as-implanted sample shows a new emission band at 506 nm, which is attributed to the production of interstitial Al atoms. The intensity of emission band at 506 nm first increased then decreased with increase in annealing temperature. For the same annealing temperature, the intensity of PL peak at 506 nm of the sample annealed in air was higher than the sample annealed in vacuum. The experimental results show that the intensity of the PL peak at 506 nm of Ar-implanted sapphire can be enhanced by subsequent annealing with an enhancement of nearly 20 times. The influence of thermal annealing of the Ar-implanted samples on the new 506 nm emission band was discussed. (C) 2009 Elsevier B.V. All rights reserved.

Stability and demulsification of emulsions stabilized by asphaltenes or resins

Experimental data are presented to show the influence of asphaltenes and resins on the stability and demulsification of emulsions. It was found that emulsion stability was related to the concentrations of the asphaltene and resin in the crude oil, and the state of dispersion of the asphaltenes and resins (molecular vs colloidal) was critical to the strength or rigidity of interfacial films and hence to the stability of the emulsions. Based on this research, a possible emulsion minimization approach in refineries, which can be implemented utilizing microwave radiation, is also suggested. Comparing with conventional heating, microwave radiation can enhance the demulsification rate by an order of magnitude. The demulsification efficiency reaches 100% in a very short time under microwave radiation. (C) 2003 Elsevier Inc. All rights reserved.

单孢融合性实验法鉴定采自四川北部的小孔异担子菌(英文)

在四川北部九寨沟和黄龙保护区的云杉、松树和铁杉上发现异担子菌 ,并从 6号标本中分离到 73个单孢菌株。在每个标本中随机选取 2个菌株分别与欧洲的原始多年异担子菌、小孔异担子菌和冷杉异担子菌的单孢菌株进行融合性交配。试验表明 ,这 6号标本都是小孔异担子菌。四川的菌株与欧洲的原始多年异担子菌交配不融合 ,而与欧洲的小孔异担子菌完全融合 ,并在交配后的菌落中形成锁状联合 ,且在交配的菌落中不产生拮抗线。虽然四川的菌株与欧洲的冷杉异担子菌有较高的融合性 ,但这些交配大部分为单项交配 ,即只在四川一侧的菌落中产生锁状联合 ,而且在交配的菌落中多数产生拮抗线。研究样品全部采自天然林 ,小孔异担子菌在四川经营林分中的致病性还有待进一步调查。

东北典型工矿城镇空间生态规划研究

空间生态规划着重于研究城乡土地和空间资源,达到城乡土地和空间资源合理配置。辽宁本溪市南芬区属山地资源型工矿城镇,由于空间用地类型配置不合理,中心城区环境污染严重,而广阔的乡村空间资源未尽其用。为此,有必要对南芬全区城乡空间进行生态规划,本文围绕生态优先、整体优化、经济优效和社会持续等方面探讨了南芬空间生态规划策略。