PbTe/CdTe量子点的光学增益

PbTe/CdTe量子点是一类新型异系低维结构材料，实验发现具有强的室温中红外光致发光现象.为研究这一材料体系的发光特性，建立了理论模型，计算了PbTe/CdTe量子点的光学跃迁和增益.模型基于k·p包络波函数方法并考虑了PbTe能带结构的各向异性.分析了量子点光学增益与量子点尺寸、注入载流子浓度的关系.结果表明，当注入载流子浓度在(0.3—3)×10¹⁸cm^-3范围时，尺寸为15—20nm的量子点可以产生 关键词： PbTe/CdTe量子点 光学增益 铅盐矿半导体

Optical gain in PbTe/CdTe quantum dots

A theoretical model is developed to study the optical transition and optical gain of PbTe/CdTe quantum dots. The model is based on the k·p envelope function approach, and anisotropic band structure characteristics of PbTe are taken into consideration. The relationships of optical gain of PbTe/CdTe quantum dots vs dot size and injection carrier density are given. The theoretical results suggest that PbTe/CdTe quantum dots with dot size of 15—20nm are promising materials for mid-infrared lasers, which may produce optical gain higher than 5000cm^-1 when the injection carrier density ranges (0.3—3)×10¹⁸cm^-3. The optical gain decreases with dot size increasing. However, higher injection carrier density is required for PbTe/CdTe quantum dots with smaller sizes (<15nm). Therefore the optimal PbTe quantum dot sizes are 15—20nm.