球型核壳量子点结构中二类激子向一类激子的转化(英文)  

Transformation from Type-Ⅱ to Type-Ⅰ Excitons in Spherical Core-shell Quantum Dots

作　　者：王志平[1] 邢雁[1] 王旭[1] 

机构地区：[1]内蒙古大学物理科学与技术学院,内蒙古呼和浩特010021

出　　处：《发光学报》2009年第4期453-456,共4页Chinese Journal of Luminescence

基　　金：Project supported by Universities Program of Inner Mongol of China (NJZZ07008);the Natural Science Foundation of Inner Mongolia of China (200607010105)~~

摘　　要：在有效质量近似下,采用变分方法研究了球型核壳量子点中激子的性质。数值计算了电子波函数随位置的变化关系以及临界势随球壳宽度和核半径的比值的变化关系。结果表明,当球壳宽度和核半径的比值为给定值时,存在一临界势,当局域势减小到临界势时,激子从二类激子转化为一类激子;当局域势为给定值时,存在一临界比值,当球壳宽度和核半径的比值减小到临界比值时,激子亦从二类激子转化为一类激子。该结果对研究球型核壳量子点中的电子结构有参考价值。The excitons in the spherical semiconductor core-shell quantum dots embedded in an insulator matrix were studied theoretically in a simplified model within the framework of effective mass approximation by using the variational approach. The calculations for the values of the wave functions as functions of coordinate, and the critical potential as functions of the ratio of shell width to core radius were performed numerically, respectively. It was found that there exists a critical potential for a given ratio of the shell width to core radius, when the potential decreases cross this critical value the exciton transforms from a typeⅡ exciton into a type-Ⅰ exciton. For a given potential, there exists a critical ratio of the shell width to core radius, when this ratio decreases cross this critical value the exciton transforms from a type-Ⅱ exciton into a type-Ⅰ exciton. The essential features were clarified, which may serve as a starting point for the analysis of excitons in real materials.

关 键 词：激子 量子点 变分法 

分 类 号：O469[理学—凝聚态物理] O472.3[理学—电子物理学]