ZnO-Based Solar Blind Ultraviolet-B Photodetectors Using MgZnO Absorption Layer

The heterostructured thin films of the solar blind p-ZnO:LiNO₃/i-MgZnO/n-MgZnO:In ultraviolet-B photodetectors were deposited at a low temperature using the vapor cooling condensation system. The photodetectors exhibited an absorption cut-off wavelength of 310 nm and did not response in the visible wavelength range. A low dark current of 20 pA and a high rejection ratio of 3.60 × 10³ were measured when a reverse bias voltage of −1 V was applied. The associated photoresponsivity of 0.2 A/W, the noise equivalent power of 9.50 × 10⁻¹² W and the specific detectivity of 3.16 × 10¹² cm Hz^1/2 W⁻¹ were obtained. Furthermore, the dominant noise originated from the flicker noise.