Ultraviolet radiation sensing in composite oxide semiconductor films

We report on the ultraviolet (UV)-radiation sensing of pulsed-laser deposited In2O3:SnO2:ZnO films grown on glass substrates. The films demonstrate sharp increase (∼0.35 Ω) in electrical resistance on UV illumination. The resistance of the films shows strong spectral (in the vicinity of 325 nm) and power dependence. This is explained due to the presence of defects located at lattice disorders that generate levels within the semiconductor band gap and originate depletion region around them when charged. This reduces the effective conduction region, increasing the effective resistance. These results show new possibilities for the low-cost high performance UV radiation sensors for biosafety.