在10K到150K低温下硅三极管电流增益的温度特性与分析

本文给出了１０Ｋ到１５０Ｋ低温下硅高频小功率晶体管是民不充增益的实验结果，发现随着温度的降低ｌｎβ－１／Ｔ曲线的斜率在减小，并且在４３Ｋ左右β值急剧增大。     

低温时半导体PN结的物理特性及玻尔兹曼常数的测量

本文验证在１５０Ｋ—２００Ｋ低温下硅半导体载流子仍然严格符合玻尔兹曼分布率     

掺铒SiO_x的光致发光特性

利用分子束外延设备生长了掺铒ＳｉＯｘ，观察到铒掺入的同时Ｏ的掺入效率也得到提高．铒可以促进氧的掺入的原因是铒与氧在硅衬底表面反应，以络合物形式掺入硅中，从而提高了硅中氧的浓度．测量了铒在ＳｉＯｘ中的光致发光特性，结果表明掺铒的ＳｉＯｘ的发光强度从１８Ｋ到３００Ｋ仅下降了约１／２，这说明Ｅｒ掺在ＳｉＯｘ中是一种降低发光强度的温度淬灭效应的途径，最后讨论了温度淬灭的机制．     

MPS结构中的光生伏特现象

报道了金属／多孔硅／单晶硅结构（ＭＰＳ）中光生伏特效应研究的最新结果，给出了该结构的光谱响应曲线，发现该结构在１１００—３５０ｎｍ波长范围具有明显的光谱响应．还测量了开路电压随温度、光照波长及光照强度的变化关系，发现开路电压随温度的降低近似线性增加，其温度系数对于金／多孔硅结构约为２.０ｍＶ／Ｋ，对于铝／多孔硅结构约为２.８ｍＶ／Ｋ，与单晶硅及非晶硅太阳电池的温度系数相近，但ＭＰＳ结构的开路电压随光强的增加不满足对数关系．结果表明，在ＭＰＳ结构中金属／多孔硅肖特基结对光生伏特效应起了主要作用，而多孔硅／单晶硅异质结的作用是与此相反的 关键词：     

重掺杂硅费米能级和少数载流子浓度的温度特性分析

费米能级和少数载流子浓度是硅半导体的重要物理参数，它们与半导体掺杂杂质种类、掺杂浓度和温度都密切相关，至今尚未有一统一的数学模型，特别是在杂质重掺杂各件下进行定量的计算。本考虑了重掺杂引起的禁带变窄效应，建立了从７７Ｋ到３００Ｋ广为适应的数学模型，着重分析了重掺杂条件下它们的温度特性，获得的计算结果与献数据较好吻合，这为低温半导体器的设计提供了有益的理论基础。     

间接原子吸收光谱法测定四氧化三钴中的微量硅

以盐酸、甲醛溶解试样,在ｐＨ１～２的盐酸介质中,硅、磷与钼酸铵生成硅钼及磷钼杂多酸。以乙酸丁酯萃取磷钼酸分离除去磷,再用ＭＩＢＫ萃取硅钼酸,因硅与钼原子数之比为１１２,利用原子吸收光谱法测定有机相中的钼,即可间接测定硅。本法测定高纯四氧化三钴中的硅有很高的灵敏度,检测限达０．２μｇ／ｍＬ,并可避免基体钴及其他共存元素的干扰。与分光光度法对照,结果满意。     

中子引起的单粒子反转截面的Monte Carlo模拟计算

单粒子效应是蠹民粒子在电子元器件中通过时，靠民电子元器件的电离损伤，导致电子元器件的记录出错。考虑了１０－２０ＭｅＶ中子与硅反应的主要反应道，利用Ｍｏｎｔｅ Ｃｑｒｌｏ方法对中子射入硅器件器中引起的单粒子反转进行模拟，得到质子、α粒子的能量、角度分布。考虑带电粒子在硅片中引起的电离 损伤，对不同临界电荷在１６Ｋ动态ＲＡＭ硅片中有一个灵敏单克发生反转时，中子入射注量及相应在的单粒子反转截面，给出了反     

结构参数F与部分气态化合物标准生成焓的相关性研究

用三个分别代表分子中原子联结情况、顶点原子结构特点和相邻原子成键情况的矩阵相乘得到一个无量纲数值的方法定义并计算了拓扑指数Ｆ。用Ｆ分别相关了１６个硅卤化物（不含氢）、３２个硅卤化物９含氢）、１６个钛卤化物、３２个硅卤化物和钛卤化物（不含氢）、４８个硅卤化物（含氢）和钛卤化物、４４个卤代甲烷的标准生成焓,其相关系数均在０．９７以上。Ｆ能较好地处理ＣＨ４、ＳiＨ４等Ｒａｎｄｉｃ－Ｋｉｅｒ指数不能处理的     

K在InP（100）表面吸附及界面反应的同步辐射光电子能谱研究

利用同步辐射光电子能谱研究了Ｋ在ｐ型ＩｎＰ（１００）表面的吸附及其界面反应。由Ｋ吸附过程中Ｉｎ４ｄ和Ｐ２ｐ芯能级谱的变化发现：在碱金属Ｋ吸附于ｐ型ＩｎＰＯ（１００）表面的过程中，Ｋ－Ｐ之间发生了化学反应，形成Ｋ－Ｐ化合物，当Ｋ覆盖度０〉２１０Ｓｅｃ时稳定的Ｋ－Ｐ化合物基本形成，此时Ｐ２ｐ峰的峰形和峰位基本保持不变。Ｋ－Ｉｎ之间无明显的化学反应发生，但在Ｋ的吸附过程中，碱金属Ｋ对Ｉｎ有置换反应发生，     

Pr掺杂对Y1—xPrxBa2Cu3O7—δ体系的自旋能隙的影响

Ｙ１－ｘＰｒｘＣｕ３Ｏ７－δ系列样品，在ｘ＝０时，Ｔｃ－９０Ｋ，电阻率ρ随温度线性变化，ｘ＝０．１，０．３，０．４，０．４５时，电阻率ρ分别在１４０Ｋ，１７５Ｋ，１８５Ｋ，１９５Ｋ以下温区，向下偏离线性，出现自旋能隙打开现象。     

Thermal conductivity and specific heat of thin-film amorphous silicon

We report the thermal conductivity and specific heat of amorphous silicon thin films measured from 5-300 K using silicon-nitride membrane-based microcalorimeters. Above 50 K the thermal conductivity of thin-film amorphous silicon agrees with values previously reported by other authors. However, our data show no plateau, with a low T suppression of the thermal conductivity that suggests that the scattering of long wavelength, low Q vibrations goes as Q2. The specific heat shows Debye-like behavior below 15 K, with theta(D) = 487 +/- 5 K, and is consistent with a very small contribution of tunneling states in amorphous silicon. Above 15 K, the specific heat deviates less from Debye behavior than does its crystalline allotrope, indicating no significant excess modes (boson peak) in amorphous silicon.     

Investigation of radiation-induced mixed interstitial configurations in a dilute nickel 1 at.% silicon alloy

Abstract

X-ray energy spectra induced by 1 MeV protons and the energy spectra of the backscattered protons have been examined in the <100> and <110> directions of Ni crystals containing 1 at.% Si. The channeling method was used to investigate interactions between the radiation-induced defects and the silicon atoms. From the measured minimum yields and from the shape of the angular scans the fraction of silicon atoms is determined, which are displaced into the <100> and <110> channels due to proton or helium irradiations and subsequent annealing treatments. In undamaged crystals about 98 % of the silicon atoms are on normal lattice sites. After irradiation a dose dependent fraction of the silicon atoms is displaced 0.05 nm away from the substitutional position indicating the formation of a mixed dumbbell consisting of one selfinterstitial atom and one silicon atom. However, the experimental data can also be interpreted by the assumption of a NiSi₂ complex, in which the silicon atoms are displaced 0.08 nm from the lattice site. Subsequent annealing from 50 K to 160 K does not change the configuration and the concentration of the silicon complexes. At room temperature the silicon atoms in the complex are positioned 0.04 nm from the lattice position. The silicon complexes were totally am ihilated at 400 K.     

扶手椅型硅纳米管的电学性质研究

本文采用密度泛函理论的第一性原理方法,对手性指数m=n=K（K为3～15的整数）的扶手型硅纳米管的能带结构和态密度进行了研究。计算结果表明,扶手型（3,3）硅纳米管为间接带隙结构,其余均为直接带隙结构;随着手性指数的增加,硅纳米管的直径增大,硅纳米管的禁带宽度逐渐减小,且导带逐渐下移,总态密度图峰值强度增大;扶手型（3,3）硅纳米管的禁带宽度最大;扶手型（13,13）硅纳米管的禁带宽度最小,说明其导电性优于其他手性指数的扶手椅型硅纳米管;同时,扶手型（4,4）硅纳米管的导带和价带出现重叠,说明扶手型（4,4）硅纳米管为金属性纳米管;态密度图表明扶手型（9,9）硅纳米管的价带顶主要由Si-3p电子态构成,导带底由Si-3p态电子和Si-3s态电子共同构成。     

Low temperature channeling measurements of ion implantation lattice disorder in single crystal silicon

Lattice disorder for 200-keV Sb implantations into silicon has been studied by channeling effect analysis using 400 keV proton backscattering. Implantation and analysis were performed at low temperatures in the same system without warmup. In the temperature region between 85°K and room temperature the disorder production per incident ion at low doses is implantation temperature dependent. Approximately 18,000 silicon scattering centers per incident 200-keV Sb ion are observed for 90°K implantations, and this value is nearly a factor of three greater than at room temperature. Isochronal anneal curves of low fluence, low temperature implantations show, significant annealing below room temperature. The observed disorder production per incident ion decreases with increasing implantation temperature at temperatures 50 to 100°K lower than annealing occurs following 85 or 90°K implants. Strong similarities of the implantation temperature dependence and anneal behavior of the disorder exist for Sb and B implantations into silicon and suggest that much of the lattice disorder produced by ion implantation can be understood in terms of the basic properties of the silicon target material.     

Phonon heat transport in silicon nanowires

Thermal conductivity of silicon and porous silicon nanowires based on the equation of phonon radiative transport is theoretically evaluated. The thermal conductivities of silicon nanowires with square cross-sections are found to match molecular dynamics simulation results reasonably well. It is shown that the results of meso-porous silicon nanowires are about two orders of magnitude lower than that of silicon nanowires in a wide range of temperature (50 K-300 K). Received 24 April 2001 and Received in final form 23 December 2001     

激光干涉法测量硅高温环境下的线膨胀系数的实验研究

利用中国计量科学研究院自行设计的基于激光干涉法的材料线膨胀系数测量装置进行了材料线膨胀系数测量试验。该装置采用单频激光干涉，对称光路设计，其干涉仪分辨率小于1nm。实验过程中改进并完善了该装置，重新设计了加热炉，改进了实验方法，使该装置在800K以上的高温环境下能进行材料线膨胀系数的测量。在800K到1200K温度范围内，对单晶硅试样采用分段加热进行测量,并对样品变化过程及测量结果作了分析，得到了单晶硅线膨胀系数的曲线，实现了在1200K环境下采用激光干涉法材料线膨胀系数的纳米级测量。     

Argon physisorption as structural probe for endohedrally doped silicon clusters

We report on an element-dependent critical size for argon physisorption at 80 K on transition-metal-doped silicon clusters. Argon does not attach to elemental silicon clusters but only to surface-located transition-metal atoms. Thus physisorption provides structural information. Specifically, the minimal cluster size for the formation of endohedral singly metal-doped silicon cages has been determined. The observed critical size for doubly doped silicon clusters indicates that larger caged molecules can be formed, eventually leading to the growth of metal-doped silicon nanorods.     

硅、锗中氧的低温红外吸收

在6—300K下,利用红外傅里叶光谱仪研究了400—4000cm^-1间的硅、锗中氧的红外吸收。采用高分辨条件时,分辨率可达0.5cm^-1。研究了在低温下利用硅的1106cm^-1吸收峰和锗的855cm^-1吸收峰探测硅和锗氧含量的探测限和误差。若样品厚度为2cm,估计在20K下,硅中氧含量探测限～9.6×10¹⁴氧原子·cm^-3,锗中氧含量探测限～3.0×10¹⁴氧原子·cm^-3。同时,对不同生长条件下直拉锗单晶的氧含量进行了研究,并与用锂沉淀法所求得的锗中氧含量加以比较。对不同氧含量的硅样品的1106cm^-1吸收峰在6—300K的变化进行了观察和讨论。 关键词：     

Thermal expansion behavior of silicon at low temperatures

Lattice parameters, thermal expansion coefficients and Grüneisen parameters of silicon are determined by an X-Ray diffraction method in the temperature range of 180–40 K without the use of liquid gases. Thermal expansion of silicon becomes negative below 120 K which is discussed in terms of its lattice vibrations and crystal structure.