ABSTRACT
zinc oxide (ZnO), with a strong exciton binding energy and wide direct bandgap, is a promising candidate for short-wavelength optoelectronic devices. The capability of fabricating ZnO at a lower temperature and the feasibility of wet-chemical etching make the integration of ZnO with silicon (Si) technology highly feasible. The indium doped ZnO thin film used in this study was deposited by ultrasonic spray pyrolysis on n-Gallium Arsenide (GaAs) wafers. Such epitaxial ZnO/Si-based heterostructured diode is promising for the development of low-cost and high-performance optoelectronic devices integrated on Si. The interface layer electron energy-loss spectroscopya (EEL) spectrum shows a similar trend as the GaAs EEL spectrum, suggesting that the interface layer has an electronic structure more closely related to GaAs than ZnO. The saturation of electroluminescence intensity is due to the limitation of the electrical-to-optical conversion efficiency caused by Auger recombination or by heating effects at high current level.
