Radiation damage in proton bomdarded gallium arsenide

Radiation damage in proton bombarded GaAs was investigated by photo-luminescence and transmission electron microscopy as a function of proton energy, dose, post bombardment anneal temperature and time of anneal. The recovery of the photoluminescence signal with temperature of anneal was measured for samples proton bombarded to doses of 1015, 1016 and 1017 cm (sup -2). Unbombarded samples showed a decrease in photoluminescence signal with temperature of anneal. All these results could be explained by an equation derived from the phenomenological theory of luminescence. The spatial distribution of the damage studied by transmission electron microscopy, showed a Gaussian distribution about a mean range which correlated closely with the Lindhard, Scharff and Schiott (LSS) projected range of protons in GaAs. The nature and distribution of the extended defects were studied as a function of dose and temperature of anneal. The Frank loops and dislocations present in the bombarded and annealed samples were analysed and their nature determined. Models are proposed to explain the observed generation of dislocations at damage rafts and to account for the formation and growth of voids and Frank loops upon annealing. From analyses of the growth processes a value of 0,3 eV for the average enthalpy of motion of a vacancy in GaAs was deduced