Luminescence measurements of laser induced recombination centers in (Al,Ga)As

Abstract

The photoluminescence of laser created recombination centers in Al0.22 Ga0.78As has been investigated in the temperature range 30–550 K. A Gaussian type of emmision profile with a half-width varying from 33 meV at 30 K to 85 meV at 300 K has been found. Profile and variation of half-width can be described by a configuration-coordinate (CC) model. The laser generated centers exhibit significant differences compared to native or thermally induced defect centers: the half-width is much smaller, the peak energy shift with temperature is negative, and the activation energy for quenching is well above room temperature. These differences are explained in terms of the CC model by an unusually low vibration energy of the ground state and possibly by a temperature variation of the separation X0 ofthe potential energy minima of the ground and excited states of the center.