ZnO films were deposited on sapphire, Si, quartz and Cornign 7059 glass substrates by r.f. sputtering. A 356 nm UV photoluminescence (PL) peak corresponding to inter-band transition was observed for the films deposited on sapphire, Si and quartz substrates when excited with 270 nm light. For the films prepared on Corning 7059 glass, only a 446 nm blue emission peak originated from electron transition from shallow donor level of oxygen vacancies to the valence band was found. After high temperature annealing in air, the intensity of PL peaks for the films onthe former three types substrates increased pronouncedly.
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