A STUDY ON ABSORPTION OF Na ATOMS ON Si(100) 2×1 SURFACES WITH DV-Xα METHOD

The Na absorption on Si(100) 2×1 surface is studied with quantum chemistry molecular cluster method. The calculated results show that the most favourable absorption site of Na is the cave site and the charge transfer of Na atom to Si is large when the Na coverage is smaller than 0.5 monolayer (ML). A Na chain is formed along the cave sites at the 0.5 ML Na coverage, the charge transfer then becomes small. The calculated density of states show that the Na atoms are metallic along the chain. At 1 ML coverage, the Na atoms occupy both the cave and pedestal sites and form a double-layer. There is a charge transfer of 0.5e from each Na atom to the Si surface. The calculated surface energy shows that the saturation absorption of Na on Si surface is 1 ML.     

Role of amorphous silicon domains of Er^3＋ emission in the Er—doped hydrogenated amorphous silicon suboxide film

An investigation on the correlation between amorphous Si (a-Si) domains and Er^{3+} emission in the Er-doped hydrogenated amorphous silicon suboxide (a-Si:O:H) film is presented. On one hand, a-Si domains provide sufficient carriers for Er^{3+} carrier-mediated excitation which has been proved to be the highest excitation path for Er^{3+} ion; on the other hand, hydrogen diffusion from a-Si domains to amorphous silicon oxide (a-SiO_x) matrix during annealing has been found and this possibly decreases the number of nonradiative centres around Er^{3+} ions. This study provides a better understanding of the role of a-Si domains on Er^{3+} emission in a-Si:O:H films.     

CW CO2激光退火在硅中产生的氧沾污

利用相衬显微术、电子吸收像、IR光谱、AES和ESCA谱研究了硅片经CW CO₂激光退火后的一些特征,其中着重分析氧的深度沾污问题。电子吸收像表明:我们的CW CO₂激光退火条件下,其效果并不很均匀。实验还证明:空气中的CW CO₂激光退火可以减少样品表面的碳沾污,但产生氧沾污。氧的沾污分两部分:表面是SiO_x,其下是自由氧原子,厚度不大于250?。 关键词：     

PHOTOELECTRON SPECTROSCOPIC STUDY OF THE EFFECT OF Cs INTRALAYER ON THE BAND LINEUP OF Ge/InP(100) HETEROJUNCTION

The formation and band lineup of the Ge/InP(100) interface with or without alkali metal Cs intralayer (IL) are studied by means of X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). It is found that the Cs atoms do not react with or diffuse into the subatrate and the Ge overlayer. The thin Cs IL will induce an increase of the valence band offset (ΔE_v) for the Ge/InP(100) heterojunction. The changes of ΔE_v are proportional to the IL thickness and them saturate for IL thickness of about one half of a monolayer of Cs IL. Without the IL, ΔE_v of the Ge/InP(100) heterojunction is equal to 0.70eV, and ΔE_v with one half of monolayer IL is up to 0.90eV. These results show that the interface dipole plays a major role in the band lineup at the heterojunction interface.     

银锌合金中的β相变

Owen与Edmunds曾经指出:银锌合金Ag-Zn由β相区骤冷后得到有序的体心立方结构β′相;缓冷则得到六角晶系ζ相;但在β相区进行高温观察,则只得无序的体心立方结构β相(图1)。然而对于相变机构及超结构β′相的性质他们并未说明。     

砷化鎵的研究及应用

引言由于半导体器件在国防及国民經济中的应用有了很大的发展,目前广泛使用的鍺、硅材料的性能已不能滿足許多新的要求了。这种情况促使科学工作者大力进行新的半导体材料的探索。近年来无論在有机方面还是无机方面都进行了不少的工作,也得到了不少有成效的結果。其中值得着重提出的是所謂三五族半导性化合物。这是由Zintl綫两旁的Ⅲ族、ν族元素化合而成的化合物(如图1所示)。     

含有50原子%Zn的Ag-Au-Zn合金的研究

合金AgAuZn₂具有一个与郝斯勒合金同晶型结构的β″相,这个β″相存在于一个相当广阔的成分范围里。事实上,β″相就是β′有序结构的超结构。伴随着,β″结构的形成晶格发生突然的收缩。关于Ag-Au替换对于原子分布的影响,也作了系统的观察。在Ag-Au替换过程中,Au和Ag的替换或多或少是无规律性的,但Zn原子则仍保持它们的适宜位置,而不受到影响。当成分偏离于理想化学式AgAuZn₂时,有序度的减小不仅仅是由于化学成分的乖异,而且Ag-An替换也产生了一些无序的排列。高温观察的结果指出:Ag多合金的β′-β转变温度随着Au含量的增加而升高,而β相只能在高温度存在。少量的Au大大地提高了由淬炼而得到的β′相的稳定度。但是Au多的合金无论是在室温和高温都是具有β′结构的。     

中子辐照含氢FZ-Si的红外吸收研究

对于中子辐照的n-FZSi(H₂),利用红外吸收光谱研究了由于辐照所产生的各种与氢有关的缺陷态。在未辐照的样品和辐照的样品中分别发现了未曾报道的1992cm^{-1和1857cm-1吸收峰。对于在n-FZSi(H₂)所引起的本征吸收峰和辐照损伤吸收峰,进行了讨论和指派。2150cm-1吸收峰则被认为是由于氢施主所引起的。 关键词：}     

集成电路中的物理问题讲座 第七讲 硅中杂质的物理行为

在化学元素周期表中,已观察到许多元素在硅中能形成电子能级.它们作为硅中的杂质,其物理行为目前只有很少数的几种(例如B,P,As等)为人们所了解,而对周期表中的绝大多数元素在硅中的物理性质研究得还远远不够. 本文根据现有的工作,论述一些杂质在硅中的物理行为. 一、Ⅲ族(B,Al,Ga)及V族 (P,As,Sb)元素 众所周知,Ⅲ,V族元素是硅中最重要的杂质.它们在硅中分别是受主和施主杂质,并在硅禁带中引入浅能级:受主能级比价带顶高上EA,施主能级则比导带底低 ED 表1列出了硅中Ⅲ,V族杂质电离能的测量值.实验测量表明,Ⅲ,V族杂质在硅中的电离能…     

忆N.F.Mott教授

读了《物理》杂志34卷第9期吴自勤和阎守胜两位同志写的关于N.F.Mott教授的纪念文章,很有感触,这使我回忆起Mott教授的一些往事.从这些往事中我深受教育,所以多年来未能忘怀。