High-performance self-powered ultraviolet photodetectors based on mixed-dimensional heterostructure arrays formed from NiO nanosheets and TiO2 nanorods

The morphology and geometry of semiconductors will affect the photoresponse performance of the mixed-dimensional heterojunction photodetectors (PDs). The self-powered UV PDs based on the mixed-dimensional heterostructure arrays are formed from the two-dimensional NiO nanosheet arrays and one-dimensional TiO2 nanorod arrays. The Fermi level position and carrier concentration of the NiO nanosheets can be adjusted by the thickness of each layer and film. The enhanced built-in potential field of the NiO/TiO2 interface decreases the charge transfer resistance and the appreciate carrier transfer path improves the photogenerated carrier separation and transfer ability without external bias. The self-powered NiO/TiO2 heterojunction device demonstrates a large responsivity of 0.86 A/W, a high detection sensitivity of 1.6×1013 Jones and a fast photoresponse time of 3 ms under the weak UV light illumination.