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

Abstract

Metal oxide semiconductors proved their usabil-ity in environmental monitoring applications and are consid-ered successful in detecting ionizing radiation. This workreports the feasibility of solution-processed metal oxidesemiconductor thin-film transistors for radiation sensing forthe first time. In particular, the effects of a wide range ofgamma radiation (100Gy to 10kGy) on the performance ofsolution-processed amorphous Indium-Gallium-Zinc-Oxide(a-IGZO) transistors are investigated. The current-voltage (IV)characterization (both output and transfer characteristics) ofIGZO-TFTs before and after irradiation are obtained to studydifferent parameters. The radiation-induced changes in TFTare mainly observed in the threshold voltage shift (Δ V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> )andthe increase of subthreshold swing. It is observed that up toa total dose of 1kGy, threshold voltage increases negatively(Vth=-1.8V at 1 kGy), and beyond 1 kGy, thresholdvoltage increases positively (Δ V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> =0.8V at 10 kGy). TheXRD and AFM data of IGZO thin-film suggests minor structuraland morphological changes after exposure to gamma irradiation. The corresponding sensitivity obtained with gammairradiation 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.