Electric field effect on the donor impurity states in zinc-blende symmetric InGaN/GaN coupled quantum dots

Abstract

Based on the effective-mass approximation, the donor binding energy in a cylindrical zinc-blende (ZB) symmetric InGaN/GaN coupled quantum dots (QDs) is investigated variationally in the presence of an applied electric field. Numerical results show that the ground-state donor binding energy is highly dependent on the impurity positions, coupled QDs structure parameters and applied electric field. The applied electric field induces an asymmetric distribution of the donor binding energy with respect to the center of the coupled QDs. When the impurity is located at the center of the right dot, the donor binding energy has a maximum value with increasing the dot height. Moreover, the donor binding energy is the largest and insensitive to the large applied electric field ( F ⩾ 400 kV / cm ) when the impurity is located at the center of the right dot in ZB symmetric In 0.1Ga 0.9N/GaN coupled QDs. In addition, if the impurity is located inside the right dot, the donor binding energy is insensitive to large middle barrier width ( L mb ⩾ 2.5 nm ) of ZB symmetric In 0.1Ga 0.9N/GaN coupled QDs.