Dimethylzinc was used as a p-type dopant in material which was grown via low-pressure metal-organic vapor phase epitaxy, using trimethylgallium and AsH3 as source materials. The hole carrier concentrations and Zn incorporation efficiency were studied by using Hall effect, electrochemical capacitance voltage profile and photoluminescence spectroscopic methods. The effect of growth parameters such as the dimethylzinc mole fraction, the growth temperature, and the AsH3 mole fraction upon Zn incorporation was studied. The hole concentration increased with increasing dimethylzinc and AsH3 mole fractions, and decreased with increasing growth temperature. This could be explained in terms of a vacancy-controlled model. Photoluminescence experiments were carried out as a function of the hole concentration (1017 to 1.5 x 1020/cm3). The main peak shifted to lower energies, and the full-width at half-maximum increased with increasing hole concentration. The hole concentration increased with increasing AsH3 mole fraction, and the main peak shifted to the lower-energy side. This could be explained by invoking a vacancy control model.

M.K.Hudait, P.Modak, S.Hardikar, S.B.Krupanidhi: Journal of Applied Physics, 1997, 82[10], 4931-7