Strategic design of carrier transport layer-free homojunction perovskite photodetector

Abstract Perovskite photodetectors (PPDs) have attracted extensive attention due to their unique material properties. However, the use of electron and hole transport layers ( ETLs and HTLs) significantly increases the complexity of design and processing and reduces the reliability of the devices. To address these issues effectively, a simple strategy of eliminating the ETLs and HTLs by employing a perovskite homojunction is proposed. In this study, we examine a numerical design of p-n homojunction-based PPD without the use of carrier transport layers (CTLs), using the Silvaco TCAD simulator. To unlock the potential of the proposed design, the effects of doping concentration, mobility, thickness, and bandgap of p-perovskite and n-perovskite on the PPD photoelectric characteristics are investigated and optimized. The simulation results illustrate that a high-performance CTL-free PPD can be achieved by forming a p-n homojunction using a thin (<200 nm) highly-doped (5 × 10 17 cm −3 ) p-perovskite layer and a thick (>600 nm) lowly-doped (5 × 10 14 cm −3 ) n-perovskite layer with suitable mobility (1 ∼ 10 cm 2 V −1 s −1 ). Under optimized conditions, our findings reveal an optimum detectivity of 7.4 × 10 13 Jones at 750 nm, the optimum responsivity is found to be 0.42 A W −1 at 675 nm and the optimum EQE is 84% at 475 nm. These results highlight the promising potential of the p-n homojunction design as a device configuration for producing high-performance and reliable commercial PPDs without any CTL.