Improved responsivity of highly reproducible performance ZnO thin film flexible UV photodetectors by piezo-phototronic effect

Exploiting piezo-phototronics effect of ZnO film ultraviolet (UV) photodetector (PD) has been confirmed as a promising way to optimize the performance of flexible devices. A flexible ZnO film UV PD was fabricated on polyethylene terephthalate substrate by utilizing radio frequency sputtering technology and conventional photolithography. The responsivity of obtained device showed a threefold increase under 10.99% tensile strain. Moreover, the device maintained good reproducibility and stability after continuous bending cycles (25/50/75/100). Separation and transport of photogenerated electron–hole pairs are responsible for the enhanced performance, which is influenced by band structure change and piezoelectric polarization at the ZnO/Au interface. The attributes of high stability, reproducibility, and sensitivity of this flexible ZnO film UV photo detector indicate that the proposed method is a promising approach to optimize flexible ZnO film optoelectronic devices based on piezoelectric effect.