Blue shift in room temperature photoluminescence from photo-chemical vapor deposited ZnO films

Abstract Highly transparent ZnO films were deposited on (001) α-Al 2 O 3 at substrate temperature in the range of room temperature to 300°C by photo-chemical vapor deposition. This enabled selective deposition of ZnO films on the selected substrate area irradiated by the light source. With the descending substrate temperature as low as 100°C, band gap widening of the films has been observed, which resulted in the shift of room temperature ultraviolet photoluminescence of ZnO from 380 nm to the shorter wavelength of 360 nm. It implies that in situ patterning of ZnO with different wavelength emission characteristics is possible on the same substrate by controlling the deposition temperature.