Enhanced photo-response of thermally treated Zinc oxide ultra-violet photon detector with furnace method and pulsed laser irradiation

Ultra-violet (UV) photodetector is fabricated by RF magnetron sputtered ZnO thin films of different thickness (50 to 400 nm). ZnO film with thickness 100 nm is found to exhibit enhanced UV photo response in comparison to that observed in the thicker films and is thermally treated by two different techniques, one by furnace method and another by pulsed laser irradiation. In the furnace method, the as-grown 100 nm ZnO thin film is post annealed in a range of temperature from 100°C to 400°C for 1 hr. The I_on/I_off ratio of furnace annealed ZnO film of thickness 100 nm at 300°C is found to be (7 × 10³) with fast response time of 50 ms in comparison to other annelead films. In the second method, as-grown 100 nm ZnO film is irradiated by pulsed Nd:YAG laser corresponding to both fundamental wavelength (1064 nm) and forth harmonics (266 nm) to modify its defects profiles. Laser (¿ = 266 nm) irradiated detector exhibits enhanced response (3.7 × 10⁴) with fast response speed (30 ms), showing its promising application for detection of low intensity UV photons.