双模自组织量子点光致发光的温度依赖性

采用稳态速率方程模型,对双模自组织量子点光致发光的温度依赖性进行了研究,模拟获得了不同温度下双模自组织量子点的光致发光光谱,并进一步研究了两组量子点分布的光致发光强度比的温度依赖性。研究表明:在低温下(<75K),两组量子点分布的发光强度比基本保持不变;随着温度的升高(75K

Temperature Dependence of Photoluminescence in Self-assembled Bimodal Quantum Dots

The study on the temperature dependence of photoluminescence(PL)is essentially important for clarifying the processes of energy relaxation and energy transfer in the self-assembled quantum dots(QDs).The unusual dependence on temperature of both the peak energy position and the width of the PL bands has been reported.The fast redshift of PL energy and the anomalous decrease of line-width with increasing tempe-rature have been attributed to thermally enhanced carrier relaxation between quantum dots due to carrier thermal emission and carrier transport through the wetting layer.The PL intensity quenches with temperature due to carrier thermal escape from the dot ground states to the states of the matrix material and/or nonradiative recombination centers.In this paper,the temperature dependence of the PL of self-assembled bimodal QDs was simulated by using a steady-state rate equation model.The temperature dependence of PL intensity ratio of two QDs populations was emphatically investigated.The results showed that,the intensity ratio remains constant at low temperature(<75 K)and increases continuously at intermediate temperature(75 K