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 x 10(3) 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 x 10(-12) W and the specific detectivity of 3.16 x 10(12) cm Hz(1/2) W-1 were obtained. Furthermore, the dominant noise originated from the flicker noise.