金刚石膜压阻效应的理论研究

在Fuchs-Sondheimer薄膜理论（F-S理论）和修正的价带分裂模型的基础上,考虑晶格散射、杂质散射和表面散射,通过求解弛豫近似下的Boltzmann方程,利用并联电阻模型从理论上研究了p-型异质外延金刚石膜的压阻效应,给出了压阻效应的计算表达式. 从理论上得到了和实验一致的压阻效应的主要特性. 提出了应力作用下分裂带间距变化的模型,对大应力时饱和压阻的理论和实验误差给出了合理解释.     

双轴晶体光轴角的计算

通过坐标变换把折射率椭球方程x~2/n_1~2 y~2/n_2~2 z~2/n_3~2=1从主介电坐标系Oxyz转换到另一个新的坐标系Ox′y′z′中,这个新的坐标系Ox′y′z′可以通过将坐标系Oxyz绕原点旋转得到.只要使新的折射率椭球方程与x′y′平面的交线是一个圆,就可以确定z′轴就是晶体的光轴.由此得出了双轴晶体光轴角的计算公式.     

p型半导体金刚石膜的磁阻效应

在p型硅(100)衬底上,采用衬底负偏压微波等离子体CVD方法进行了p型异质外延金刚石膜的生长.用O₂等离子体刻蚀技术将金刚石膜刻蚀成长条形,利用四探针法在0—5T的磁场范围内测量了样品的磁阻.实验结果表明,p型异质外延金刚石膜可以产生较大的磁阻.在Fuchs-Sondheimer(F-S)薄膜理论的基础上考虑晶格散射、杂质散射和表面散射,通过求解Boltzmann方程,利用并联电阻模型研究了p型异质外延金刚石膜的磁阻效应,给出了磁阻和金刚石膜厚度、迁移率、空穴密度及磁场的关系.讨论了表面散射和价带形变对p型异质外延金刚石膜磁阻的影响,初步解释了p型异质外延金刚石膜产生较大磁阻的原因 关键词： 金刚石膜 异质外延 磁阻效应 电导率     

Near-Infrared Properties of Hybridized Plasmonic Rectangular Split Nanorings

The near-infrared properties of gold rectangular split nanorings （RSNs） are investigated by simulation using the finite element method. In the results, the distribution and enhancement of electromagnetic （EM） fields are confirmed by the distribution of charge and current density. The spectrum variation with split distance of RSNs in absorption is in accordance with the hybridization theory. The influence of split distance and light wavelength on the enhancement of EM field is also studied for devices that make use of surface plasmon resonance in nearinfrared, such as in optical trapping, biomedicine, and solar energy. Additionally, the spectra in mediums with various refractive indices suggest the potential application of the hybridized plasmonic RSNs as an ultra-sensitive sensor in the near-infrared region.     

Light focusing in linear arranged symmetric nanoparticle trimer on metal film system

Benefiting from the induced image charge on film surface,the nanoparticle aggregating on metal exhibits interesting optical properties.In this work,a linear metal nanoparticle trimer on metal film system has been investigated to explore the novel optical phenomenon.Both the electric field and surface charge distributions demonstrate the light is focused on film greatly by the nanoparticles at two sides,which could be strongly modulated by the wavelength of incident light.And the influence of nanoparticle in middle on this light focusing ability has also been studied here,which is explained by the plasmon hybridization theory.Our finding about light focusing in nanoparticle aggregating on metal film not only enlarges the novel phenomenon of surface plasmon but also has great application prospect in the field of surface-enhanced spectra,surface catalysis,solar cells,water splitting,etc.