Baira Mourad, Salem Bassem, Madhar Niyaz Ahmad, Ilahi Bouraoui
Micro-Optoelectronic and Nanostructures Laboratory, Faculty of Sciences, University of Monastir, Monastir 5019, Tunisia.
CNRS, LTM, CEA-Leti, University Grenoble Alpes, 38054 Grenoble CEDEX 9, France.
Nanomaterials (Basel). 2019 Jan 19;9(1):124. doi: 10.3390/nano9010124.
Intersubband optical transitions, refractive index changes, and absorption coefficients are numerically driven for direct bandgap strained GeSn/Ge quantum dots. The linear, third-order nonlinear and total, absorption coefficients and refractive index changes are evaluated over useful dot sizes' range ensuring -like Γ-electron energy state to be lower than -like L-electron energy state. The results show strong dependence of the total absorption coefficient and refractive index changes on the quantum dot sizes. The third order nonlinear contribution is found to be sensitive to the incident light intensity affecting both total absorption coefficient and refractive index changes, especially for larger dot sizes.
对于直接带隙应变GeSn/Ge量子点，通过数值计算得出了子带间光跃迁、折射率变化和吸收系数。在有用的量子点尺寸范围内评估了线性、三阶非线性以及总的吸收系数和折射率变化，确保类Γ电子能态低于类L电子能态。结果表明，总的吸收系数和折射率变化强烈依赖于量子点尺寸。发现三阶非线性贡献对入射光强度敏感，这会影响总的吸收系数和折射率变化，特别是对于较大尺寸的量子点。
