Heterogeneous Integration of Chiral Lead–Chloride Perovskite Crystals with Si Wafer for Boosted Circularly Polarized Light Detection in Solar‐Blind Ultraviolet Region

Abstract Chiral hybrid organic–inorganic perovskites (HOIPs) have been well developed for circularly polarized light (CPL) detection, while new members that target at solar–blind ultraviolet (UV) region remain completely unexplored. Here, an effective design strategy to demonstrate circular polarization‐sensitive solar–blind UV photodetection by growing wide‐bandgap chiral HOIP [( R )‐MPA] 2 PbCl 4 (( R )‐MPA = methylphenethylammonium) single crystals onto silicon wafers, with well‐defined heterostructures, is reported. The solid mechanical and electrical connection between the chiral HOIP and silicon wafer results in strong built‐in electric field at heterojunction, providing a desirable driving force for separating/transporting carriers generated under CPL excitation at 266 nm. Unexpectedly, during such a transport process, not only the chirality of HOIP crystal is transferred to the heterostructure, but also the circular polarization sensitivity is significantly amplified. Consequently, anisotropy factor of the resultant detectors can reach up to 0.4 at zero bias, which is much higher than that of the pristine single‐phase chiral HOIP (≈0.1), reaching the highest among the reported CPL–UV photodetectors. As far as we know, the integration of chiral HOIP crystals with silicon technology is unprecedent, which paves a way for designing boosted‐performance CPL detectors in solar–blind UV region as well as for other advanced optoelectronic devices.