The effect of Gamma irradiation on the stability of amorphous InGaZnO metal-semiconductor-metal UV photodetectors

Crystalline semiconductors are durable, but are susceptible to damage by radiation. This study irradiates amorphous InGaZnO (a-IGZO) metal-semiconductor-metal (MSM) photodetectors (PDs) with gamma rays up to 100 kilo-Gray (kGy). The current-voltage (I-V) measurements show that the ideality factor increases slightly and the Schottky barrier height decreases only marginally when the cumulative dose is increased, which demonstrates that a-IGZO retains its electronic characteristics and is not significantly affected by exposure to the maximum cumulative dose. This is attributed to the nature of amorphous phase. The photoresponse of the PDs increases slightly as the cumulative dose is increased. This is because more oxygen vacancies are induced, which produces more electrons and the photocurrent is increased. Therefore, a-IGZO is eminently suited to use as an active layer for radiation-resistant PDs.