Halide perovskites exhibit excellent electrical and optical properties and are ideal candidates for active layers in optoelectronic devices,especially in the field of high-performance photodetection,where they demonstrate a competitive advantage in terms of development prospects.Among them,the all-inorganic perovskite CsPbBr3 has received widespread attention due to its better environmental stability.It is demonstrated in this work that a vertical MSM-type CsPbBr3 thin-film photodetector has characteristics of fast response time and ultra-low dark current.The use of a vertical structure can reduce the transit distance of photo carriers,enabling the device to achieve a fast response time of 63 μs,which is two orders of magnitude higher than the traditional planar MSM-type photodetectors with a response time of 10 ms.Then,by spinning a charge transport layer between the p-type CsPbBr3 and Ag electrodes,effective separation of photocarriers at the interface is realized and physical passivation between the perovskite and metal electrodes is also achieved.Due to the superior surface quality of the spun TiO2 film compared with the NiOx film,and through Sentaurus TCAD simulations and bandgap analyses,with TiO2 serving as the electron transport layer,it effectively inhibits the transmission of excess holes in p-type CsPbBr3.Consequently,the electron transport layer TiO2 is more effective in reducing dark current than the hole transport layer NiOx,with a dark current magnitude of only-4.81 ×10-12 A at a-1 V bias.Furthermore,this vertical MSM-type CsPbBr3 thin-film photodetector also has a large linear dynamic range(122 dB),high detectivity(1.16×1012 Jones),and good photo-stability.Through Sentaurus TCAD simulation,it is found that the charge transport layer selectively blocks carrier transmission,thereby reducing dark current.The simulation results are in good agreement with experimental data,providing theoretical guidance for a more in-depth understanding of the intrinsic physical mechanisms.
关键词
CsPbBr3/光电探测器/垂直结构/低暗电流/高响应速度
Key words
CsPbBr3/photodetector/vertical structure/low dark current/high response speed
万方数据