多孔硅的形成机制及吸收特性

Forming Mechanism of Porous Silicon and Its Optical Absorption Properties

用测量多孔硅反射谱的方法研究了多孔硅在吸收边附近的特性。由于多孔硅的微空洞和残余部分大约只有纳米量级，故采用波长为２００～２６００ｎｍ的红外到紫外范围的光照射，根据多层膜的反射公式，计算出多孔硅在吸收边附近的吸收系数。结果表明（αｈω）２与（ｈω－Ｅｇ）呈线性关系，表明多孔硅在一定程度上已转变为直接带隙半导体。

The absorption properties of porous silicon near the absorption edges are studied using the reflection spectrum method for measuring porous silicon in this paper. Since the micro pores and residual parts of porous silicon are only about the nanometer (nm) scale, the illumination with the wave length of 200 2600 nm from the infra red to the ultraviolet is adopted. The absorption coefficient of porous silicon near the absorption edges can be calculated in accordance with the reflection equation of multi layer films. The results indicate that there is a linear relation between(αhω) 2 and (hω E g) and also that porous silicon has been transformed into the semiconductor with direct gaps to some extent.