Shallow-donor impurity in vertical-stacked InGaN/GaN multiple-quantum wells: Electric field effect

Based on the effective-mass approximation, the electric field effect on the shallow-donor impurity states in vertical-stacked zinc-blende (ZB) InGaN/GaN multiple-quantum wells (MQWs) is investigated variationally. Numerical results show that if the electric field applied to the right (along the growth direction), the donor binding energy has a maximum value and the position of the maximum value is located inside the left well. Moreover, in the presence of the electric field, the donor binding energy of impurity located at the center of the left well is insensitive to the increment of the barrier width when the barrier width is large. In particular, it is also found that the donor binding energy of impurity located at the center of the left well in the MQWs has a maximum value with the increase in electric field and the critical electric field of the maximum value is reduced when the well width is increased. (C) 2010 Elsevier B.V. All rights reserved.