Ultraviolet Photodetection Application in Magnesium Indium Oxide Thin Film Transistors via Co-Sputtering Deposition

A magnesium-doped indium oxide (In2O3:Mg) ultraviolet (UV) thin film phototransistor was fabricated via cosputtering of MgO and In2O3. Three samples with different sputtering power values of In2O3 ranging from 40 to 60 W, namely, sample A with 40 W, sample B with 50 W, and sample C with 60 W, were used in this study. Results confirmed that oxygen vacancy concentration evidently indicates indium content. The experimental results showed that responsivities of samples, defined as the ratio of photocurrent under illumination per input power, increase from 0.0086 to 2.6 A/W. Rejection ratios were 1.2 × 104, 4.3 × 105, and 4.8 × 105 for samples A, B, and C, respectively. Based on our results, sample C is the best among the three MgInO UV phototransistors investigated in this study.