有机半导体研究中的导纳谱方法

随着有机电子学的发展,导纳谱方法受到越来越多的关注.本文在导纳谱原理的基础上,总结了目前有机半导体研究中使用的几种导纳谱物理模型,概述了导纳谱在研究载流子迁移率方面的应用,并对导纳谱在定域态分布、负电容现象和其他一些应用研究进行了介绍.     

Influence of post-annealing on the properties of Ta-doped In<Subscript>2</Subscript>O<Subscript>3</Subscript> transparent conductive films

Ta-doped In₂O₃ transparent conductive oxide films were deposited on glass substrates using radio-frequency (RF) sputtering at 300°C. The influence of post-annealing on the structural, morphologic, electrical and optical properties of the films was investigated using X-ray diffraction, field emission scanning electron microscopy, Hall measurements and optical transmission spectroscopy. The obtained films were polycrystalline with a cubic structure and were preferentially oriented in the (222) crystallographic direction. The lowest resistivity, 5.1×10⁻⁴ Ω cm, was obtained in the film annealed at 500°C, which is half of that of the un-annealed film (9.9×10⁻⁴ Ω cm). The average optical transmittance of the films was over 90%. The optical bandgap was found to decrease with increasing annealing temperature.     

Hydrogen absorption properties of amorphous (Ni0.6Nb0.4−yTay)100−xZrx membranes

Ni based amorphous materials have great potential as hydrogen purification membranes. In the present work the melt spun(Ni_(0.6)Nb_(0.4-y)Ta_y)_(100-x)Zr_x with y=0, 0.1 and x=20, 30 was studied. The result of X-ray diffraction spectra of the ribbons showed an amorphous nature of the alloys. Heating these ribbons below T 400 °C, even in a hydrogen atmosphere(1-10 bar), the amorphous structure was retained. The crystallization process was characterized by differential thermal analysis and the activation energy of such process was obtained. The hydrogen absorption properties of the samples in their amorphous state were studied by the volumetric method,and the results showed that the addition of Ta did not significantly influence the absorption properties, a clear change of the hydrogen solubility was observed with the variation of the Zr content. The values of the hydrogenation enthalpy changed from ~37 k J/mol for x=30 to ~9 k J/mol for x=20. The analysis of the volumetric data provides the indications about the hydrogen occupation sites during hydrogenation, suggesting that at the beginning of the absorption process the deepest energy levels are occupied, while only shallower energy levels are available at higher hydrogen content, with the available interstitial sites forming a continuum of energy levels.     

三层磁性耦合膜的磁化过程

从理论上计算了三层磁性耦合的磁化过程。假定每层膜具有单轴各向异性，且易轴方向垂直于膜面，各层磁化曲线都为矩形。第一层与第三层组成成份和膜厚完全相同。我们得到了各种各样磁化过程及其条件。尤其指出了得到矩形磁化过程条件。磁光记录需要矩形磁化过程，为进一步多层膜磁光记录研究提供了依据。     

溅射参数对非晶态CoFeNiNbSiB软磁薄膜性质的影响

系统研究了溅射工艺对非晶磁性薄膜的影响,发现在不同的氩气压下,薄膜的磁学性质随负偏压有不同的变化关系。采用电子探针、扫描电子显微镜等测试手段,发现在不同的溅射条件下,非晶膜的微观结构不同。在较高氩气压下,膜中会出现许多圆柱形结构,从而引起膜的软磁性能下降。分析了造成这种结构差别的原因。采用最佳溅射条件,制出了性能优良的非晶态软磁薄膜。     

掺杂半导体的电离率

本文从电子占据能级的几率出发,经过严格数学推导,得到了杂质半导体的电离率、电离能、浓度及温度各量关系的一般表达式,并与某些极端条件下的近似结果进行了比较。分析表明,本文得到的表达式具有普遍意义,该关系式对于分析上述各量关系,特别是在非极端条件下,具有实际意义。     

直接带隙半导体系统中的磁相互作用

运用精确的量子蒙特卡洛技术,研究了直接带隙半导体系统（Haldane-Anderson模型）中的磁相互作用.精确的数值解揭示了两种截然不同的自旋关联函数,均没有显示出明显的RKKY振荡行为;并且随着不同参数的变化,自旋关联函数呈现相当复杂的多因素控制的显著特征.这些行为对于理解一些磁性的半导体系统会有很大帮助,例如,稀磁半导体等.     

a－Si：H和a－SiC：H薄膜掺杂效率的研究

本文通过测量掺杂ａ－Ｓｉ：Ｈ和ａ－Ｓｉｃ：Ｈ薄膜的电导率随退火温度和退火时间变化研究了温度对掺杂效率的影响以及杂质激活的微观过程。结果表明，（１）杂质激活过程是伸展指数形式，（２）在低温区掺杂效率正比于，（３）在高温区掺杂效率达到一饱和值。通过一个与氢运动有关的杂质激活模型，我们解释了上述实验结果。     

在不同靶温条件下氦离子注入InGaAsP化合物半导体形成高阻层的研究

本文研究了在不同靶温条件下，Ｈｅ＋离子注入Ｎ型（ｎ＝１×１０１８ｃｍ－３）ＩｎＧａＡｓＰ形成的高阻层。结果表明，注入区的表面电阻和注入剂量，注入后的退火条件及注入靶温有关。在高剂量区（＞１×１０１４ｃｍ－２），低靶温（８０Ｋ）高靶温（５２３Ｋ）下注入的样品比室温（３００Ｋ）下注入的样品，具有较高的表面电阻和温度稳定性。卢瑟福背散射（ＲＢＳ）沟道测量的结果表明，这一高阻层和注入形成的非晶层有密切关系。