Preparation Of Organic-Inorganic Hybrid Perovskite-Based Two-Dimensional Materials And Research Of Their Photodetectors Performance

Two-dimensional organic-inorganic hybrid perovskite materials are expected to become star candidate materials for high-performance semiconductor photodetectors due to their advantages such as high absorption coefficient,high photovoltaic conversion efficiency,high carrier mobility,and long carrier lifetime.In particular,materials like CH3NH3PbI3(MAPbI3)hold tremendous potential in optoelectronic applications.However,there are still some issues in the fabrication of organic-inorganic hybrid perovskite semiconductor devices.(1)One problem is that organic-inorganic hybrid perovskite materials are soluble in water,alcohol,acetone,and other solvents,which makes traditional photolithography methods inapplicable.Therefore,current preparation methods for semiconductor devices using this material mostly rely on mask-assisted techniques and auxiliary protective photolithography.However,the quality of devices prepared by mask-assisted techniques is currently poor and difficult to control,while auxiliary protective photolithography cannot directly test the intrinsic optoelectronic properties of perovskite.(2)Most of the current strategies for optimizing the performance of two-dimensional organic-inorganic hybrid perovskite materials in photodetectors involve forming heterojunctions with traditional two-dimensional materials such as graphene,transition metal sulfides,or black phosphorus.However,due to the different physical and chemical properties between the two materials,issues like high dark current and significant noise may arise.Therefore,utilizing two types of perovskite materials to form heterojunction structures might solve this problem.To address the aforementioned issues,this study proposes a new transparent template nanofabrication(t-SL)technique using a focused ion beam(FIB)micro-nanomachining system.This technique demonstrates optimal processing accuracy of 100 nm and is completely transparent,allowing easy visualization of the target material on the substrate through the template.Additionally,the template exhibits good repeatability,greatly reducing the fabrication cycle of semiconductor devices and improving device quality.By employing this method,the authors successfully fabricated photodetectors of MAPbI3 and BA2MAPb2I7 with channel widths of 500 nm,achieving excellent optoelectronic performance.Under weak laser irradiation of 1μW/cm2,the photodetectors of MAPbI3 and BA2MAPb2I7 demonstrated responsivities of 8.6 A/W and 4.2 A/W,respectively,with corresponding detectivities of 1.8×1012 Jones and 2.2×1012 Jones.To further improve the performance of the photodetectors,the study fabricated two-dimensional MAPbI3/BA2MAPb2I7 heterojunction photodetectors.Under laser irradiation with a light power density of 1 μW/cm2,the photodetector achieved a responsivity of 28.3 A/W,which is 5 times and 9 times higher than that of MAPbI3 and BA2MAPb2I7 devices,respectively.Additionally,the detectivity of the photodetector reached 1.5×1013 Jones,which is one order of magnitude higher than that of MAPbI3 and BA2MAPb2I7 devices.These findings demonstrate the excellent performance of heterojunction photodetectors and provide valuable insights for the fabrication of perovskite photodetectors.It is worth noting that the outstanding performance of the photodetectors is attributed to their heterojunction structure.Furthermore,the study also proposed a novel hBN/Gr/1D CH3NH3PbI3 mixed van der Waals heterojunction photodetector.The research results demonstrate that the mixed van der Waals heterojunction achieves efficient transfer of photo-generated carriers from nanowires to graphene electrodes,significantly improving the responsivity and detectivity of the photodetector,which are measured as 558 A/W and 2.3×1012 Jones,respectively.Moreover,due to the encapsulation of hexagonal boron nitride(hBN),the device exhibits excellent stability in air,maintaining its performance for over two months.Additionally,the study observed polarization-sensitive light detection,attributed to the influence of the device’s geometric shape.These results provide an effective solution for the development of high-performance and air-stable organic-inorganic hybrid perovskite nanowire electronic/photonics devices.