Broadband Photodetector Based on Inorganic Perovskite CsPbBr₃ /GeSn Heterojunction

Photodetectors with broadband response spectrum have attracted great interest in many application areas such as imaging, gas sensing, and night vision. Here, a high performance broadband photodetector is demonstrated with inorganic perovskite CsPbBr₃ /GeSn heterojunction, detection range can be covered from 450 to 2200 nm. The responsivity of heterojunction device can achieve as high as 129 mA W^-1 under illuminated light of 532 nm, which is 4.92 times larger than that of a GeSn based device. As the CsPbBr₃ can also act as anti-reflective coating for infrared wavelength, the infrared band responsivity at wavelength of 2200 nm can also be raised by 1.42 times. In addition, the device with all inorganic components is showed good stability, while keeping in the dry environment, the device can sustain its 90% original after 550 h storage. These results show the inorganic perovskite/GeSn heterojunction device is of great potential in broadband photodetection with high responsivity.