Novel Self-Powered Photodetector with Binary Photoswitching Based on SnSx/TiO2 Heterojunctions.

Binary photoresponse characteristics can realize the optical signal processing and logic operations. The UV photodetectors (PDs) with SnSx nanoflakes and TiO2 nanorod arrays (NRs) show a novel binary photoswitching behavior (change in current from positive to negative) by manipulating the light wavelength without external power source, utilizing the interfacial recombination of the photogenerated carriers in the type-I SnSx/TiO2 heterojunctions. The enhanced responsivity (R*) and detectivity and fast photoresponse time for self-powered SnSx/TiO2 PDs can be achieved by adjusting the phase ratio of SnS and SnS2 nanoflakes. The binary photoswitching in the self-powered UV PDs can be applied in the encrypted optical signal processing and imaging in some special conditions without external bias.