Piezoelectricity enhanced self-powered solar-blind ultraviolet photodetectors based on Ga2O3/ZnO heterojunction

Amorphous Ga ₂ O ₃ (a-Ga ₂ O ₃ ) films have attracted extensive attention in the field of photodetectors due to their excellent photoresponse and photoelectric properties. However, there is limited research on harnessing piezoelectricity to modulate the photoresponse of a-Ga ₂ O ₃ photodetectors. In this work, self-powered solar-blind ultraviolet (UV) photodetectors (PDs) based on a-Ga ₂ O ₃ /ZnO heterojunctions were constructed by the magnetron sputtering method. The photoresponse behaviors of a-Ga ₂ O ₃ /ZnO PD can be regulated by the piezoelectricity. Under 254 nm light and 0 V bias, the responsivity and detectivity of a-Ga ₂ O ₃ /ZnO PD at 0.57% tensile strain reached 2.69 mA/W and 1.56×10 ¹⁰ Jones, respectively, which are 46.2% and 35.7% higher than those without strain. Moreover, the rise/decay times were shortened from 85.2/83.7 ms to 50.6/43.4 ms. The enhancement in performance of a-Ga ₂ O ₃ /ZnO PD was attributed to the improvement of the conduction band discontinuity between a-Ga ₂ O ₃ and ZnO, which could be beneficial for quick transfer of photogenerated electrons from the a-Ga ₂ O ₃ layer to the ZnO layer. These findings have implications for the design and fabrication of piezoelectricity-enhanced photodetectors.