ZnSe/ZnS抛物量子阱中激子的极化子效应(英文)

采用推广的LLP方法研究了ZnSe/ZnS抛物量子阱中激子的极化子效应。考虑电子和空穴与LO声子的相互作用,得到了激子基态能量和结合能随阱宽的变化关系。结果表明,阱宽较小时,能量随着阱宽的增大而急剧减小;阱宽较大时,能量减小的比较缓慢。和我们以前的工作对比,我们发现ZnSe/ZnS抛物量子阱对激子的束缚强于GaAs/Ga1-xAlxAs抛物量子阱。

Polaron Effects of Exciton in ZnSe/ZnS Parabolic Quantum Wells

ZnSe-related quantum well structures have attracted much interest with regard to their optoelectronic application. They have large optical nonlinearity due to the large exciton binding energy compared with the IB-V compound semiconductors. The ZnSe/ZnS quantum well structure is a promising material for fabricating laser diodes since they have a direct band gap with wide band gap energy up to 3.75 eV at room temperature. The purpose of the present work is to investigate the polaron effects of the exciton in the ZnSe/ZnS parabolic quantum well (PQW). We assume the trial function has a simple form with the variables describing the motion within the quantum well plane separated from those describing the motion along the growth axis. The interaction of the charged particles with bulk longitudinal optical( LO) phonons is considered only, and the energy of the system is obtained by using a variational method developed by Lee, Low and Pines . The results showed that the ground state energy and the binding energy of the exciton with LO-phonon decrease rapidly with increasing the well width L at the beginning, then decreases very slowly with increasing L. In contrast to our previous work, it can be found that the exciton in the ZnSe/ZnS PQWs is more strongly bound than that in the GaAs/Ga1-XAlXAs PQWs.