A flexible bilayer p-NiO/n-ZnO films with photodetecting properties in self power mode

We report highly efficient flexible p-NiO/n-ZnO heterojunction UV photodetectors. NiO and ZnO thin films were grown on plastic polyethylene terephthalate (PET) substrates by dc magnetron sputtering for constructing high quality interfaces. The diode has shown an excellent rectification ratio i.e. 106 under dark mode and observed more than 80% transparency in the visible region. Investigated structural, compositional, and optical properties of the film to correlate the UV photodetector transport characteristics. Further, UV illumination devices exhibit an excellent responsivity of 0.24 A W−1 with a detectivity of 1.25 × 1011 jones and the highest external quantum efficiency of 83.14% achieved at −5 V of bias. The device shows the fastest speed of response with rise/fall times of 86.10 ms/106.60 ms, accomplished at −1 V with the lowest optical power density. The photodiode has shown incredible characteristics that are mainly attributed to the built-in potential and the transport mechanism at the interface.