Developement of a new modulation spectroscopy by exciting polarized light

点击翻译按钮获取中文摘要

We developed a new modulation technique for semiconductor quantum structures by using polarization anisotropy. We focus our attention on reflectance signal modulated by polarized light. The summary of this research are followed. (1) In order to develope an analysis method, we theoretically investigated dielectric functions at semiconductor surfaces. (2) We developed a new in-situ characterization system to observe electronic states during the crystal growth. A probe light irradiate the sample surface, and the polarization modulated signal was detected. It was found that the incident angle of the probe light is important to observe the surface electronic states. (3) An anisotropic character was observed for the p and s waves of the probe light, which reflect the anisotropy of the dielectric function coming from surface morphology and surface reconstructions.This realizes a new sensitive detection of electronic states localized at the surface. By using this technique, we can observe the electronic states changed by the abrupt surface and adsorped atoms. (4) Our developed system can measure a modulation spectrum and its dynamic character during the growth. This technique promises a practical use of the in-situ modulation spectroscopy.