The External Field Effects On GaAs/GaALAs And The ZiNc-blende InGaN/GaN Quantum Well

In recent years, there has been an increasing interest in the low-dimensional semiconductor heterostructures because of their specific physical properties and promising applications in the optoelectronic devices. Moreover, several research results show that the presence of impurity, external field (such as electric field, laser field an so on), temperature, hydrostatic pressure has obvious effects on the optical and electrical properties of semiconductor optoelectronic devices. In this paper, based on the effective-mass theory and variational method, the effects of laser field and temperature on the ground-state donor binding energy in a GaAs/Ga1-xAlxAs quantum well (QW) are investigated. Moreover, the combined effects of the laser field, the electric field and the pressure on impurity states in the zinc-blende (ZB) InGaN/GaN quantum well (QW) are analyzed and discussed.(1) To investigate the effects of the laser field and temperature on the ground-state donor binding energy in a GaAs/Ga1-xAlxAs quantum well (QW), by means of a variational method within the framework of effect-mass approximation, we calculate explicitly the ground-state donor binding energy as a function of the impurity position, laser parameter, temperature, Al composition and well width. The main conclusions obtained are given as follow:The laser field leads to a decrease of the impurity donor binding energy in the case of any temperature, well width, impurity position and Al composition. The laser field obviously affects the donor binding energy of impurity near the center of QW. However, the effect of the laser field on the donor binding energy becomes less pronounced as the impurity lies at the boundary of the QW. In particular, for impurity located at Z=L/2, the donor binding energy first slowly increases, reaching a maximum value, and then decreases. The laser field have more remarkable effect on the donor binding energy of impurity in the QW with small size. In addition, our results also show that the increase of temperature decreases the donor binding energy of impurity for any given impurity position, laser parameter, Al composition and well width. The donor binding energy increases as the Al composition x increases. The donor binding energy decreases as the well width increases. However, for the QW with big size, the amplitude of variation the ground-state donor binding energy tends to be weak.(2) To investigate the combined effects of the laser field, the electric field and the hydrostatic pressure on impurity states in the zinc-blende (ZB) InGaN/GaN quantum well (QW), the ground-state donor binding energy is calculated variationally as a function of the impurity position, hydrostatic pressure, the electric field and well width within the framework of the effective-mass approximation. Numerical results show that the hydrostatic pressure increases the donor binding energy of impurity located at different impurity positions for any the electric field and laser field case. When applied laser field and electric field is weak, the hydrostatic pressure affects obviously the impurity donor binding in the zinc-blende (ZB) InGaN/GaN quantum well (QW). Moreover, the hydrostatic pressure has obvious effects on the impurity states in the zinc-blende (ZB) InGaN/GaN quantum well (QW) with small size. The donor binding energy decreases with increasing the laser field for any case. The electric field decreases the donor binding energy, and it makes the donor binding energy show the asymmetrical distribution with respect to the center of QW. In the presence of the laser field, the influences of the electric field and hydrostatic pressure on the impurity states are weaken. Moreover, the electric field effects on the impurity states are much more obvious in the QW with large well width and small hydrostatic pressure cases. In addition, the pressure and laser field have a significant influence on the binding energy of impurity located at the center of the zinc-blende (ZB) InGaN/GaN QW.