V defects of ZnO thin films grown on Si as an ultraviolet optical path

V defects were observed in the ZnO films epitaxially grown on the ZnS-buffered Si. Although the defects were located on the surface, strong near-bandedge emission confined to the {101̄1} facets of V defects was observed at room temperature. The near-bandedge emission spreads out over the whole film centering at V defects at 30 K. The detailed optical characterization shows that activation of excitonic absorption is responsible for this unique optical behavior.