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硅是间接禁带半导体,禁带宽度为1.11eV不可能在可见光区发光。1990年,Canham发现电化学阳极氧化制备的多孔硅(porous silicon缩写为PS)样品在室温下出现强烈的光致荧光现象。从此PS引起人们的极大兴趣。大量的实验结果表明PS的光致荧光现象是PS层中的量子限制效应的结果。本课题组曾研究了PS样品制备后的氧化处理与光致荧光谱的关系,从一个侧面支持了量子限制效应导致PS光致荧光的机理。PS的电化学形成过程独具特色,因为硅电极并不像其他电极那样在阳极溶解时表面原子逐层剥落,而是在硅表面形成许多直径为微米至纳米级的小孔,小孔的交叠产生了具有抗溶解特性的一根根很细的硅柱。目前有一些PS形成机理的研究报道,但引入量子限制效应观点的不多。 本文研究了PS的光致荧光谱和制备时的电流密度及HF溶液浓度的关系,结合量子限制效应讨论了PS的电化学形成过程。
Silicon is an indirect band-gap semiconductor with a forbidden band width of 1.11eV, making it impossible to emit light in the visible region. In 1990, Canham found that porous anodic oxide prepared porous silicon (PS) samples showed intense photoluminescence at room temperature. PS from this caused great interest in people. A large number of experimental results show that the photoluminescence of PS is the result of the quantum confinement effect in PS layer. Our group studied the relationship between the oxidation treatment and the photoluminescence (PL) spectra after PS sample preparation, and supported the mechanism of quantum confinement induced PS fluorescence from one side. PS electrochemical formation process is unique, because the silicon electrode is not like the other electrodes in the anode dissolution of the surface atoms peeled off layer by layer, but the surface of the silicon to form many microns to nanometer-sized holes, holes pay Stacks produce a very fine silicon column with anti-dissolution properties. There are some reports on the formation mechanism of PS, but there are not many views on introducing quantum confinement effect. In this paper, the relationship between the photoluminescence spectrum of PS and the current density and concentration of HF solution was studied. The electrochemical formation of PS was discussed with the quantum confinement effect.