摘要
在有效质量近似下,利用量子力学密度矩阵理论,从理论上研究了考虑极化子效应后核壳量子点中线性、三阶非线性以及总的光吸收系数在不同条件下随入射光能量变化的关系。通过数值计算,分析了电子-LO声子和电子-IO声子相互作用对ZnS/CdSe柱型核壳结构量子点光吸收系数的影响。结果表明,极化子效应对光吸收系数有很大影响,不同声子模式对光吸收系数影响大小不同。考虑电子-LO声子后,光吸收系数被大大提高。另外,入射光强和弛豫时间对系统的吸收系数也有很大影响。
The polaron effects on the linear and nonlinear optical absorption coefficients are investigated theoretical- ly for electrons confined in a core-shell quantum dot. The interactions of electrons with the confined longitudinal opti- cal （LO） and the interface optical （IO） phonon modes in the core-shell system are investigated. An analytic formula for the optical absorption is derived with compact-density-matrix approach and iterative method. The optical absorp- tion coefficients in a ZnS/CdSe core-shell quantum dot （QD） are calculated numerically for different pump photon energies, incident optical intensities and relaxation times. Results show that the optical absorption coefficients are de- pendent on the photon energy and relaxation time dramatically. Moreover, when the electron-LO phonon interaction is considered, the optical absorption coefficient is enhanced more than 2 times.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2017年第5期580-586,共7页
Chinese Journal of Luminescence
基金
Supported by National Natural Science Foundation of China(11547018)
Research Foundation of Education Bureau of Hubei Province(Q20142706)
Natural Science Foundation of Hubei Engineering University(z2013028)
Natural Science Foundation of Hubei Province(2014CFB579)~~
关键词
极化子
核-壳量子点
光吸收
polarons
core-shell quantum dot
optical absorption
