Near-infrared polarization-sensitive photodetection<i>via</i>interfacial symmetry engineering of an Si/MAPbI₃heterostructural single crystal

Abstract

Methylammonium lead iodide (MAPbI₃) single crystals (SCs) have drawn particular attention in the optoelectronics field, due to their outstanding photoelectric performance. However, the structures of those MAPbI₃ SCs are isotropic, which limits the further application of the materials for polarization-sensitive photodetection. Here, we propose a strategy of symmetry modulation by heterogeneously integrating large-sized MAPbI₃ SCs with silicon (Si) wafers and we give the first demonstration of self-powered near-infrared (NIR) polarization-sensitive photodetection using MAPbI₃ SCs. Created <i>via</i> a delicate solution method, the MAPbI₃/Si heterostructures show a high crystalline quality and a solid interfacial connection. More importantly, the built-in electric field resulting from the band bending at the MAPbI₃/Si heterostructure interface generates polar symmetry, which enables directional transport of photogenerated carriers, making the MAPbI₃/Si heterostructures highly polarization-sensitive. Consequently, in the self-powered mode, NIR photodetectors of MAPbI₃/Si heterostructures exhibit large polarization ratios of 3.3 at 785 nm and 2.8 at 940 nm. Moreover, a high detectivity of 7.35 × 10¹² Jones of the present devices is also achieved. Our work gives the first demonstration of self-powered polarization-sensitive photodetection of MAPbI₃ SCs and provides a strategy to design polarization-sensitive materials beyond the conventional limitations induced by isotropic structures.