Effects of pressure, temperature, and electric field on linear and nonlinear optical properties of InxGa1-xAs/GaAs strained quantum dots under indium segregation and In/Ga intermixing phenomena

Abstract

Linear and nonlinear optical properties of InxGa1-xAs/GaAs lens-shaped quantum dots were investigated, taking into account simultaneous effects of indium segregation, In/Ga intermixing, temperature, pressure, external electric field, strains, and structure dimensions. Muraki's model was used for the indium segregation and a Gaussian distribution along the growth axis and radial direction for the atoms intermixing phenomenon. All simulations were carried out using the Finite Difference Method and the effective mass approximation. Nonlinear optical properties associated with refractive index changes and light absorption were evaluated and discussed on the basis of the calculated intersubband transition energies. The results showed that the mentioned parameters have a significant effect in controlling and tuning the nonlinear optical properties. It is shown that the indium segregation inside the wetting layer brought about a blue shift, whereas inhomogeneous indium distribution inside the QDs caused a red shift. Moreover, the nonlinear optical properties underwent a prominent stark-effect, and the resonant energy's red or blue shift is related to the electric field orientation. Furthermore, the nonlinear optical properties achieved a red (blue) shift with the increase in temperature (pressure). Thus, under the combined effects of the mentioned parameters, our theoretical results were correlated with the experimental data from photoluminescence spectra.