Temperature and hydrostatic pressure effects on exciton–phonon coupled states in semiconductor quantum dot

Abstract

We studied theoretically the exciton–phonon coupled states in a cylindrical quantum dot (QD) under hydrostatic pressure and temperature effects. We calculated the exciton binding energy by using a variational approach within the effective-mass approximation. The stress is applied along the QD growth axis and the interactions of charge carriers (electron and hole) with both the confined LO phonon modes and surface phonons (TSO and SSO) are incorporated in our calculation. The effect of these three phonon modes on the exciton binding energy is discussed in the presence of pressure and temperature effects. The numerical computation for GaAs/Ga1-xAlxAs QD has shown that the exciton binding energy is very significant with increasing pressure and decreasing temperature. Both the exciton binding energy and its polaronic correction increase linearly with increasing stress. We investigated also the effects of the temperature and pressure on the integrated photoluminescence (PL) intensity, and show that at relatively high temperature the phonons have a noticeable effect on it. This physical parameter also shows a great dependence on pressure.