Fabrication and characterization of ZnO film based UV photodetector

ZnO films were deposited on Al2O3 substrates by metalorganic chemical vapor deposition (MOCVD) at temperatures of 400, 450 and 500 A degrees C. The photoconductivity of the films has been analyzed for ultraviolet detector application. The changes in photoresponse and current-voltage (I-V) are correlated with the deposition temperatures and microcrystalline structures. The study suggested that the photoresponse originating from bulk- and surface-related processes. For a film deposited at 400 A degrees C, a 1 ms fast rising time and a 5 ms fall time were observed. The photoresponsivity is 24 A/W with a 3 V bias.