Donor impurity effects on optical properties of GaN/AlN constant total effective radius multishell quantum dots

Abstract

In the current work, we have studied the effect of a single donor impurity confined within GaN/AlN constant total effective radius multishell quantum dots (CTER-MSQDs) on optical properties, intersubband transition energies, and normalized ground-state wave functions. Systems with different numbers of wells and inner radius of the quantum dot have been explored. We have shown that systems with the largest inner quantum dot radius R1 values have the smallest intersubband transition energies in both systems with and without donor impurities. Now, it is possible to localize the electron in any part of our quantum dot structure by changing the number of wells and inner quantum dot radius R1. We also show that in the presence and absence of the donor impurity, maximum absorption decreases when R1 increases. Absorption band edges experience a redshift by increasing of the R1 values for systems with a small number of wells, while they experience a blueshift by increasing of the R1 values for systems with a larger number of wells. Adding the impurity does not affect the absorption coefficient of CTER-MSQDs with R1=400 Å and R2=600 Å. Maximum absorption of the studied systems decreases when we add the impurity. Finally, when R1 increases, the refractive index changes gradually decrease for systems with a small number of wells and increase for systems with a large number of wells.