High Responsively and Ultrafast Photodiode Based on Vertical Junction of Silicon and Two-Dimensional Lead Iodide Perovskite: Effects of Active Area

Two-dimensional (2-D) perovskites are gaining significant attention as promising materials for optoelectronic applications due to their unique optical and electrical properties along with their good stability compared to their three-dimensional (3-D) counterparts. In this study, we present the successful fabrication of a photodetector based on the heterojunctions of silicon (Si) and the 2-D Ruddlesden–Popper-phase perovskites of (CH3 (CH2)3NH3)PbI4 and (CH3 (CH2)3NH3)2(CH3NH3)Pb2I7. The vertical junction of 2-D lead iodide perovskite and p-type Si is responsible for photocharge generation in this type of photodetectors. We investigate the effects of active area on the responsivity of the 2-D perovskite/Si-based photodetector. The best performance is achieved for the device with
$80\times 80\,\,\mu \text{m}^{{2}}$
active area that is about the crystal grain size in 2-D perovskite. The detector shows high sensitivity as high as 100 A/W in the visible and near infrared (NIR) ranges, which is a noticeably high and competitive responsivity among devices with similar architectures. Although perovskite-based devices suffer from low stability, the fabricated device shows stable performance without needing encapsulation.