PHOTOLUMINESCENCE PROPERTIES OF ZNTE LAYERS GROWN BY PHOTO-ASSISTED METALORGANIC VAPOR-PHASE EPITAXY

Effects of light illumination on the photoluminescence (PL) properties of ZnTe has been investigated by using epitaxial layers grown with different carrier gases, transport rate of source materials and light sources or by introducing triethylaluminum (TEAl) as a dopant. Free exciton emission can be observed in only the epitaxial layers grown with illumination under H-2 atmosphere, implying that the illumination is effective for the growth of good quality ZnTe layers. The illumination strengthens the transition due to excitons bound to donor impurities, namely Cl which is substituted into Te lattice site, at low substrate temperature. These effects are closely related to the use of photons having an energy higher than the bandgap of ZnTe. It seems that the photo-assisted metalorganic vapor phase epitaxy (MOVPE) technique also brings about the effective formation of Al donor by suppressing the generation of the complex of Al and Zn-vacancy in the ZnTe epitaxial layer.