Research on piezo-phototronic effect in ZnO/AZO heterojunction flexible ultraviolet photodetectors

Abstract A novel Al-doped (3 wt%) ZnO (AZO) UV photodetector (PD) and ZnO/AZO heterojunction double-layer UV PD were prepared on a polyethylene terephthalate (PET) substrate by utilizing the radio frequency (RF) sputtering technology and conventional photolithography. Because the ZnO/AZO heterojunction possesses the ability to improve the separation of the photogenerated electron-hole pairs, the responsivity of the ZnO/AZO PD is higher than that of the pure AZO PD under the same bias voltage. Moreover, the responsivity of the obtained ZnO/AZO PD showed a 1.13 fold increase from 5.91 to 6.70 A/W when the tensile variable ɛ was 0.16. These findings also provide a new alternative for the preparation of flexible UV PDs with piezo-phototronic effect, which is low-cost and offers environmental sustainability.