Enabling bipolar photoresponse improvement of a-GaOx/Hf0.5Zr0.5O2 heterojunction self-powered solar-blind photodetector by coupling ferro-pyro-phototronic effect

Gallium oxide-based (GaOx-based) photodetectors possess outstanding weak solar-blind signal detection capability due to low background noise. The bipolar photodetectors with polarity-switchable photoresponse take advantage of multi-dimensional signal recognition and signal processing efficiency. However, as-reported bipolar photodetectors are limited primarily to complex multi-layer heterojunction architectures based on either multi-wavelength absorption or a competitive photoresponse mechanism. The lack of a regulation scheme for implementing and optimizing polarity-switchable photoresponse of simple-structured GaOx-based photodetectors becomes a bottleneck for friendly integration and efficient signal recognition. Herein, introducing a ferroelectric component endows amorphous GaOx/Hf0.5Zr0.5O2 (a-GaOx/HZO) heterojunction photodetectors with programmable self-powered characteristics. The self-powered solar-blind photodetector (SSBPD) exhibits boosted polarity-switchable photoresponse by the coupling of ferro-pyro-phototronic effect. A switchover between positive to negative photoresponse is enabled by switching polarization from the upward state to the downward state. Photo-induced pyroelectric effect boosts bipolar photoresponse of the SSBPD characterized by four-stage photocurrent dynamic behavior. Under superposition contributions of programmable ferroelectric polarization and pyroelectric effect, the photoresponse enhancement factor of the SSBPD is 341% (226%) under upward (downward)-polarization state. Correspondingly, the maximum responsivity and detectivity are up to 0.26 mA/W and 4.47 × 108 Jones, respectively. The SSBPD maintains excellent durability over a wide temperature range. Based on programmable bipolar photoresponse, a-GaOx/HZO photoelectric device displays application prospects in simulating a self-adaptive neuromorphic vision system and a nighttime anti-collision monitoring system. This work proposes a strategy to develop simple-architecture GaOx-based bipolar photodetectors by multiple-effect coupling.