High-quality ZnO films prepared on Si wafers by low-pressure MO-CVD

High-quality ZnO films were successfully prepared on Si wafers by low-pressure MO-CVD using zinc acetylacetonate (Zn(C5H7O2)2) and oxygen. The c-axis oriented ZnO films were grown on p-type Si wafers at temperature of 520 deg. C with ZnO buffers layers deposited by RF sputtering. Although, the ZnO layer deposited by sputtering has a poor c-axis orientation, the films prepared by MO-CVD on the ZnO buffer layer shows a sharp X-ray diffraction peak at 34.4 deg. corresponding to the (0002) of hexagonal ZnO. Room temperature photoluminescence spectrum of the all film exhibits a strong peak consisted of near-band edges emission at 378 nm. Current-voltage characteristics of the ZnO(n)/Si(p) heterojunction exhibits non-linear and rectifying characteristics with a small current leakage in the reverse direction. A dark-blue light was clearly observed around the periphery of the top Al electrode by applying forward bias voltages