Variation of surface morphology with precursor supply ratio in MOVPE CdTe layers

Correlations of surface morphology with the growth characteristics and optimal doping conditions of (100) CdTe layers grown by metalorganic vapor phase epitaxy have been studied. Growths were carried out on (100) GaAs substrates using diethyltellurium (DETe) and dimethylcadmium (DMCd). Pyramidal hillocks characterized the surface morphology at DETe/DMCd flow ratios below unity, where high p-type doping by arsenic was achieved. By increasing the DETe/DMCd flow ratio from 1 to 2, the surfaces started to show smooth and specular morphologies, where high n-type doping by gallium was achieved. For DETe/DMCd flow ratios exceeding 2, the surfaces changed to show ellipse-like pits which were considered to be due to Te precipitate.