Linear and nonlinear optical properties of semi-elliptical InAs quantum dots: Effects of wetting layer thickness and electric field

Abstract

In this paper, we have studied the optical properties of semi-elliptical InAs quantum dots (QDs) embedded in GaAs. Under effective mass approximation, the finite element method has been used to obtain wavefunctions and corresponding energy eigenvalues in three-dimension. It has been shown that the wetting layer (WL) thickness has a small effect on the (1-2) transition, but is more effective on the dipole moment matrix element (DMME) of the (2-3) and (1-3) transitions. It is seen that the linear absorption coefficients of the (2-3) and (1-3) transition reach the maximum at 4 A WL thickness. After that, we set the WL thickness to 4 A and we studied the effect of the electric field applied through the axial direction. The same as the WL effect, the electric field has caused a minor change in DMME of the (1-2) transition but it makes DMME of the (2-3) and (1-3) transitions stronger which results in very high linear absorption coefficients. For 20kV/cm electric field intensity, the linear absorption coefficient reaches the maximum for the (2-3) and (1-3) transition.