A GaN/PbI2 Heterostructure Photodiode For Harvesting Lights from UV to Green band

Recently, two-dimensional (2D) lead iodide (PbI2) has attracted extensive attention in efficient photodetection owing to its promising optical properties, while the high performance PbI2 based photodetector is still in the early stage. In this work, we have reported a green recycled PbI2 based heterostructure photodetector with GaN as its building block for photo-sensing lights from UV to green band. At 9 V bias voltage, the fabricated photodetector exhibits a photoresponsivity of 34.5 mA/W and a detectivity of 7.5 × 109 Jones. The device also shows a fast response with a rise time of 68.7 µs and a decay time of 20.1 µs, respectively. In addition, the wavelength depended responsivity can be adjusted by the direction of the bias voltage, by which the photo-active region of the heterostructure is subsequently modulated. Under 1250 cycles on-off switching illumination of 442 nm laser, the photodetector maintains excellent stability and repeatability. The photo-response of the device to the IR light band is further studied, and shows distinct pyroelectric effect and temperature depended carrier enhancement. The as-prepared photodetector indicates a great potential of the recycled PbI2 for next-generation optoelectronic devices.