Chunyan Wu, Bin Zeng, Kunnan Zhou, Longqiang Shan, Junjie Wang, Li Wang, Yizhong Yang, Yuxue Zhou, 

and Linbao Luo

Abstract: In this work, we demonstrate the fabrication of GaAs photodetector with grating-perovskite (G-PVK) for a broadband enhanced ultraviolet (UV)-near infrared (NIR) photodetection. The device shows a peak photoresponse under 530 nm illumination, presenting a responsivity of 0.3 A/W, a specific detectivity of 2.24×10¹⁰ Jones and 0.6 ms/0.56 ms for rise/fall time, respectively. Compared to the device without PVK, the dark current was suppressed by 2 orders of magnitude and the photoresponse was enhanced up to 215%. This should be ascribed to the effective spatial separation of the vertical build-in electric field between GaAs and G-PVK and the enhanced light trapping arising from the diffraction grating. The well-aligned grating also shows a high sensitivity to the polarized light, giving rise to a peak-to-valley ratio I_max/I_min of about 2.14. This suggests the potential application of the device in the polarization-sensitive imaging system