DX-center energy level dependence on silicon doping concentration in Al0.3Ga0.7As
The Hall free carrier concentration of silicon-doped Al0.3Ga0.7As alloys is studied as a function of both temperature and illumination. Different thermal activation energies were observed for the DX center as a function of silicon concentration. Excitation of the samples using an infra-red source also provided data for better insight into the DX center population. We correlated the incremental free electron photo persistent population with the activation energies obtained from the temperature dependence of the measured Hall concentration. We concluded that large free carrier concentrations can yield perturbations in the lattice potential that may alter the configuration coordinate energy barriers for capture and emission of electrons by and from the DX centers.