High-performance Al-doped ZnO flexible ultraviolet photodetector via piezo-phototronic effect

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.