DX-CENTER ENERGY-LEVEL DEPENDENCE ON SILICON DOPING CONCENTRATION IN AL0.3GA0.7AS

The Hall free carrier concentration of silicon-doped Al0.3Ga0.7As allo ys is studied as a function of both temperature and illumination. Diff erent 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 ce nter population. We correlated the incremental free electron photo per sistent population with the activation energies obtained from the temp erature dependence of the measured Hall concentration. We concluded th at large free carrier concentrations can yield perturbations in the la ttice potential that may alter the configuration coordinate energy bar riers for capture and emission of electrons by and from the DX centers .