A Solution Processed Amorphous InGaZnO Thin-Film Transistor-Based Dosimeter for Gamma-Ray Detection and Its Reliability

Metal oxide semiconductors proved their usability in environmental monitoring applications and are considered successful in detecting ionizing radiation. This work reports the feasibility of solution-processed metal oxide semiconductor thin-film transistors for radiation sensing for the first time. In particular, the effects of a wide range of gamma radiation (100Gy to 10kGy) on the performance of solution-processed amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) transistors are investigated. The current-voltage (IV) characterization (both output and transfer characteristics) of IGZO-TFTs before and after irradiation are obtained to study different parameters. The radiation-induced changes in TFT are mainly observed in the threshold voltage shift ( $\sf \Delta ~\text{V}_{th}$ ) and the increase of subthreshold swing. It is observed that up to a total dose of 1kGy, threshold voltage increases negatively ( $\sf \Delta \,\,\text{V}_{th}= -1.8\text{V}$ at 1 kGy), and beyond 1 kGy, threshold voltage increases positively ( $\Delta \,\,\text{V}_{\text{th}} =0.8\text{V}$ at 10 kGy). The XRD and AFM data of IGZO thin-film suggests minor structural and morphological changes after exposure to gamma irradiation. The corresponding sensitivity obtained with gamma irradiation is 27.78 mV/Gy (100Gy-1kGy), expressed in the threshold voltage shift. The effects of radiation-induced changes in TFTs are completely removed after storing irradiated TFTs in the vacuum at room temperature for 6 months.