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.