Fabrication and performance of N-doped ZnO UV photoconductive detector

We report study on the fabrication and characterization of an ultraviolet (UV) photodetectors based on N-doped ZnO films. The N-doped ZnO films with 10 at% N doping are spray deposited on to alumina substrates. The photoconductive UV detector based on N-doped ZnO thin films, having a metal–semiconductor–metal (MSM) configuration are fabricated using Al as a contact metal. The dependence of I–V characteristic under dark and illumination, spectral and transient photoresponse of the detector are investigated. The linear current–voltage (I–V) characteristics under forward bias exhibit ohmic metal–semiconductor contact. The UV photoconductive effect is observed showing fast response with switching on/off UV light illumination. The neutralization of photogenerated holes by negatively charged oxygen ion plays a key role in the photoconductive characteristics of N-doped ZnO polycrystalline films.

► Growth of N doped ZnO films on sapphire by spray pyrolysis. ► Reflectance of pure and N doped ZnO. ► UV detectors using N doped ZnO on ZnO buffer. ► UV detector exhibits highest spectral responsivity.