Electron and impurity states in GaN/AlGaN coupled quantum dots: Effects of electric field and hydrostatic pressure

Abstract

Based on the effective mass approximation, the ground-state donor binding energy of impurity located at the surface of the zinc-blende (ZB) GaN/AlGaN symmetric coupled quantum dots (SCQDs) is investigated variationally, considering the combined effects of the electric field to the right (along the growth direction) and the hydrostatic pressure. Numerical results show that the impurity localized inside the left dot, the donor binding energy is insensitive to the middle barrier width of the ZB GaN/AlGaN SCQDs if the middle barrier width is large. While the hydrostatic pressure increases the donor binding energy for any electric field and impurity position. Moreover, the hydrostatic pressure has a remarkable influence on the donor binding energy of impurity localized inside left dot. In addition, the competition effects between the electric field and hydrostatic pressure (between the electric field and quantum confinement) on the donor impurity states in the ZB GaN/AlGaN SCQDs have also been investigated in detail, which may be very interesting to understand the impurity states in semiconducting nanostructures.