| Affiliation: | 1. Department of Electrical Engineering, National Cheng Kung University, Tainan, 70101 Taiwan;2. Department of Electrical Engineering, National Cheng Kung University, Tainan, 70101 Taiwan
Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Tainan, 711010 Taiwan;3. Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Tainan, 711010 Taiwan;4. Department and Institute of Electrical Engineering, Minghsin University of Science and Technology, Hsinchu, 30401 Taiwan;5. Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung, 81148 Taiwan |
| Abstract: | This research demonstrates a state-of-the-art vertical-transport photodetector with an n-type 3D MAPbI3/p-type quasi-2D (Q-2D) BA2MA2Pb3I10 perovskite heterojunction. This structure introduces a ≈0.6 V built-in electric field at the n-p junction that greatly improves the characteristics of the perovskite photodetector, and the presence of Q-2D perovskite on the surface improves the life. The electrical polarities of the 3D and the Q-2D perovskite layers are simply controlled by self-constituent doping, making clearly defined n-p characteristics. Doctor-blade coating is used to fabricate the photodetector with a large area. The Q-2D materials with highly oriented (040) Q-2D (n = 2,3) planes are near the surface, and the (111) preferred planes mixed with high index Q-2D materials (n = 4,5) are found near the 3D/Q-2D interface. The stacking and interface are beneficial for carrier extraction and transport, yielding an external quantum efficiency of 77.9%, a carrier lifetime long as 295.7 ns, and a responsibility of 0.41 A W−1. A low dark current density of 6.2 × 10−7 mA cm−2 and a high detectivity of 2.82 × 1013 Jones are obtained. Rise time and fall time are fast as 1.33 and 10.1 µs, respectively. The results show the application potential of 3D/Q-2D n-p junction perovskite photodetectors. |
