正入射全自动扫描反射率绝对值光谱仪的研制

采用Ｍ型棱镜分光束法研制了一台全自动扫描绝对反射率光谱仪，测量光谱范围为３５０ｎｍ～８２０ｎｍ（１．５～３．５ｅＶ），样品入射角为５°，测量和数据采集处理全过程由计算机控制．测量绝对值精度优于±１％，测量重复性优于０．１％．采用本谱仪对热蒸发金膜和（１１１）锗本征体单晶进行测量，获得了与椭偏测量以及文献报道相一致的结果．     

STUDY OF PHOTON-TRAPPING PHENOMENON IN POROUS SILICON LAYER

Porous silicon samples were prepared for optical studies by using the photoluminescence (PL), Raman scattering (RS), as well as the absolute reflectance and ellipsometry methods. Results show that the porous Si has low optic constants, and can trap the visible photons of more than 95%, but give no evidence of a strong interband transition existing in the vis-ible region. The Bruggeman effective-medium-approximation (EMA) and Lorentz oscillator models were used in data analyses. Calculations show that the layer dispersion effect may result in a red shift of the PL peak. The possible mechanism for the PL and Raman enhance-ment as well as the photon trap phenomenon was discussed, and was attributed mainly to the random multiple micro-reflections in the porous-Si layer having extremely large internal micro-Burfaces.     

可变入射角波长扫描RPA型椭偏仪的研制

设计制作了一台用同步旋转起偏器和检偏器（转速之比为１：２）测量方式的波长扫描型椭偏仪。由于附加了一个固定偏振器以消除光源的部分偏振性，实验信号包括一个直流成分和四个交流成分，其频率分别为ω０，２ω０，３ω０和４ω０，利用四个交流成分中的任意三个便可以得到材料的复介电函数，实验结果的自洽度优于０．５％。并详细介绍了系统的设计、定标和校正过程，利用该椭偏仪对Ａｕ和ＣｄＴｅ样品复介电函数的测量结果与其它报道一致。