Visible-blind wide-dynamic-range fast-response self-powered ultraviolet photodetector based on CuI/In-Ga-Zn-O heterojunction

Transparent p-n diodes based on heterojunctions of p-type Cut polycrystalline layers and n-type amorphous In-Ga-Zn-O (a-IGZO) layers can be fabricated at room temperature. Cut effectively absorbs UV light owing to the simultaneous occurrence of band-to-band and excitonic transitions at room temperature. As a result, the CuI/a-IGZO heterojunction diodes exhibit clear photovoltaic effect under weak UV irradiation, even though the Cut layers are as thin as similar to 30 nm. The photocurrent at zero bias quickly tracks the on/off signals of the UV irradiation, and thus the CuI/a-IGZO heterojunctions serve as a UV photodetector (UVPD) operating in self-powered mode. The CuI/a-IGZO-based UVPD features a wide dynamic range and excellent linearity of the responsivity against UV radiation intensity. Therefore, the CuI/a-IGZO heterojunction is a promising candidate to produce a self-powered rapid-response wide-dynamic-range UVPD that exhibits excellent linearity. (C) 2019 Elsevier Ltd. All rights reserved.