The Photoluminescence Properties of Self assembled and Nano sized Silicon Quantum Dots

【中文摘要】 用 Si H4 气体的减压 CVD法 ,在氧化硅以及石英基板上自然形成了高密度的 (～ 10 11cm-2 )纳米尺寸的半球状硅晶粒 (硅量子点 ) ,并且对其光学吸收和发光 (Photo- luminescence,PL)特性进行了评价。用表面热氧化了的硅量子点样品 ,在室温条件且在高于 1.2 e V以上的能量范围内观察到了 PL谱。随着量子点尺寸的减少 ,PL谱的光学吸收限移向高能方向。 PL谱的峰值能呈现大幅度的 (约 0 .9e V)斯塔克移动 ,并且 PL谱的强度几乎与温度无关 ,说明发光来自与局域能级相关联的发光和复合过程。 【英文摘要】 Using the low pressure CVD method with SiH 4 gas, we have accumulated the silicon quantum dots in self assembled and nano sized on a silica glass substrate. The optical absorption and photoluminescene spectra have been observed. With decreasing the size of silicon quantum dot, the limit of optical absorption shifts to higher energy. The intensity of photoluminescence spectrum is independent of temperature, which means that the photoluminesce...福建省自然基金资助项

A NEW TECHNIQUE FOR OBTAINING THE “MOBILITIES SPECTRUM” TRANSIENT THERMOELECTRIC EFFECT

【中文摘要】 介绍了瞬时热电效应法，一种新的实验手段．它基于脉冲激光照射引起的载流子的扩散现象．观测到的瞬时热电电压由光激发导致的传导载流子的扩散形成，并且复合着几个特征的衰减过程指数地衰减．分析这些衰减过程，可以获得载流子的迁移率、有效质量、费密面的变化等重要信息．对瞬时热电效应法的原理以及主要分析方法作了较详细的介绍． 【英文摘要】 Abstract We introduced a new technique called “Transient Thermoelectric Effect (TTE)”, which was based on carrier diffusion as irradiated by a pulsed laser. The observed TTE voltages decayed exponentially with time, showing a multi relaxation process with characteristic relaxation times τ i(i=1,2,3,…) for thermal diffusions of photo induced conduction carriers, analyses of these results could give valuable information about carrier mobilities, effective masses and Fermi surfaces. The principle and the m..