Hydrogenic impurity states in zinc-blende InGaN/GaN asymmetric coupled quantum dots

Abstract

Based on the effective-mass approximation, the ground-state donor binding energy in cylindrical zinc-blende (ZB) InGaN/GaN asymmetric coupled quantum dots (QDs) is investigated variationally. Numerical results show that the ground-state donor binding energy is highly dependent on the impurity positions and asymmetric coupled QDs structure parameters. The donor binding energy is distributed asymmetrically with respect to the center of the asymmetric coupled QDs. The position of the maximum value is located inside the wide QD. When the impurity is localized inside the middle barrier layer, the donor binding energy has a maximum value with the variation of any dot height in ZB InGaN/GaN asymmetric coupled QDs. In particular, for the impurity localized inside the wide dot, the donor binding energy is insensitive to large middle barrier width ( L m b ≥ 3 nm ) in the ZB In 0.1Ga 0.9 N/GaN asymmetric coupled QDs.