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Al-doped ZnO (AZO) flexible ultraviolet (UV) photodetectors were fabricated on polyethylene terephthalate substrates by radio frequency magnetron sputtering technique at room temperature. The single-layer AZO photodetector has a high photocurrent/dark current ratio and exhibits excellent photoresponse performance under UV illumination. When the tensile strain increases from 0 to 0.33, the photocurrent gradually increases, and the sensitivity and linear dynamic range increase by 10 times and 1.5 times, respectively. Under 23.5 mW/cm2 UV illumination at 4 V bias, the rise time and fall time are 0.2 and 0.3 s, respectively, showing that the AZO flexible UV photodetector has good reproducibility and stability. The energy band diagrams before and after applying tensile strain are analyzed to further study the interface modulation behavior. The results reveal that the piezo-phototronic effect has an important influence on the performance optimization and modulation of flexible UV photodetectors.

Al-doped ZnO (AZO) thin films were deposited on p-type silicon (p-Si) substrates by radio frequency magnetron sputtering technology. The crystal structure, morphology characterization and elemental analysis show that AZO film grows along the c-axis (002) orientation without other impurities. The current-voltage and current-time characteristics under different illumination conditions demonstrate that the Au/AZO/p-Si diode has typical rectification behavior, excellent stability and repeatability. The photocurrent is proportional to the intensity of ultraviolet irradiation, and the photocurrent reaches 110 μA at a bias voltage of 5 V under 11.75 mW/cm2 ultraviolet light irradiation. By calculating the conduction band and valence band offset values of AZO/p-Si heterojunction, the energy band diagrams at different bias states are constructed to explain the photoelectric response behavior. These results will be helpful for the design of high-performance photodiodes.