Broadband photoresponse in plasmon-enhanced Ga-doped ZnO

In recent decades, zinc oxide (ZnO) has received considerable attention as a wide direct bandgap semiconductor for high-performance ultraviolet optoelectronic devices. However, ZnO-based photodetectors suffer from intrinsic challenges that limit their performance in fast-response and broadband photodetection. Herein, we develop Ga-doped ZnO (GZO) photodetectors with localized surface plasmon resonance (LSPR) properties. Ga doping extends the optical response range of ZnO devices to the near-infrared region (1064 nm). Furthermore, the photothermoelectric (PTE) effect results in an intriguing current polarity reversal phenomenon. Finally, the coupling of black phosphorus nanocrystals further improves the performance of the photodetector. This study provides a promising noble-metal free plasmon-enhanced photodetector, which has great potential for use in broadband photodetection and bipolar signal communication.