A Deep UV Sensitive ${\rm Ta}_{2}{\rm O}_{5}/{\rm a-IGZO}$ TFT

The authors report the fabrication of a deep-ultraviolet (deep-UV) sensitive a-IGZO thin-film-transistor (TFT) with a Ta₂O₅ gate dielectric. It was found that carrier mobility, threshold voltage and subthreshold swing were 48.5 cm²/Vs, 1.25 V and 0.49 V/decade, respectively, when measured in dark. It was also found that measured current increased from 1.5×10^-9 A to 5.56×10^-5 A , as we illuminated the sample with λ = 250 nm UV light when V_G was biased at 0 V. Furthermore, it was found that deep-UV-to-visible rejection ratio could reach 1.0×10⁶ for the fabricated Ta₂O₅/a-IGZO TFT.