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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的量子点可以产生大于5000cm-1的光学增益,增益峰位于400meV(3.1μm)附近.量子点尺寸的增大使得增益峰强减小,而量子点尺寸的减小又导致产生光学增益需要更高的注入载流子浓度,优化的PbTe量子点尺寸为15—20nm.
PbTe / CdTe quantum dots is a new type of low-dimensional heterogeneous low-dimensional structure materials, the experiment found that there is a strong room temperature mid-infrared photoluminescence.In order to study the light-emitting properties of this material system, a theoretical model was established, calculated PbTe / CdTe quantum Point optical transition and gain.The model is based on the kp envelope wave function method and takes into account the anisotropy of the band structure of the PbTe.The relationship between the optical gain of the quantum dot and the quantum dot size and the carrier injection concentration is analyzed.The results show that Quantum dots with a size of 15-20 nm yielding an optical gain greater than 5000 cm-1 with a gain peak at 400 meV (3.1 μm) with an implant carrier concentration in the range of (0.3-3) × 10 18 cm-3. Quantum dot size Increasing the peak intensity of the gain decreases, and the decrease of the size of the quantum dots results in higher injection carrier concentration for generating optical gain. The optimized size of the PbTe quantum dots is 15-20 nm.