銻砷化銦鎵合金材料的光學特性研究

Abstract

本論文藉由光激螢光技術研究銻砷化銦鎵材料的復合機制以及能帶參數。論文第一部分利用時間解析激發相干技術量測樣品生命期並討論復合機制：在室溫以及低溫情況下，樣品生命期均隨電洞濃度上升呈現一次方反比下降，在室溫高濃度端甚至較砷化銦鎵以及銻砷化鎵材料的生命期更長。配合上改變功率的量測，我們認為其少數載子電子生命期是由夏克禮-里德-霍爾複合所主導。論文第二部分利用光調制反射光譜決定此四元材料的能隙彎曲以及瓦西尼經驗參數。配合上光激螢光光譜以及變溫量測，我們觀察到中間組成樣品因受合金不均勻而產生了明顯的載子侷限效應以及更大的史托克位移量。

Band gaps and recombination mechanisms in the InxGa1-xAs1-ySby/InP materials are investigated by photoluminescence (PL), photoreflectance (PR), and time-resolved excitation correlation spectroscopy (TREC). First, we study the recombination lifetimes in heavily Be-doped InxGa1-xAs1-ySby films by TREC measurements. The dependence of electron lifetime on doping concentration can be well described by a relation and the electron lifetimes are longer than InGaAs and GaAsSb at a high doping concentration. From the power-dependent TREC measurements, we demonstrate that the carrier recombination is dominated by the Shockley-Read-Hall process. Second, the band gap bowing and the Varshni empirical parameters of undoped InGaAsSb films are determined by PR spectra. By temperature-dependent PL measurements, stronger carrier localizations and larger Stoke shifts are observed in samples with intermediate compositions.