Influence of Annealing Ambience on TiO₂Film Ultraviolet Photodetector

Abstract

This study focuses on TiO2 thin films grown on quartz substrates using radio frequency magnetron sputtering. These films were annealed under argon, air, oxygen, and nitrogen ambients via a fused-silica tube furnace, and were then used to fabricate metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PDs). Further, all fabricated detectors exhibited a low dark current. Finally, we observed that under an N2 ambient, we could acquire the best parameters for annealing TiO2 UV PDs, with a maximum responsivity of 1.73 × 10−2 A/W, while the UV-to-visible rejection ratio achieved five orders of magnitude with a 330-nm illumination at 10 V applied bias. We attributed the reduction in dark current to the filling of oxygen vacancies from N2; hence, the response was improved. We believe that this method can be used to develop a highly-applicable and low-cost device.