BiOCl‐Assisted Ultralow Temperature Growth of Large‐Area Monolayer ReSe₂ for Infrared Photodetectors Array

Abstract The 2D material rhenium selenide (ReSe 2 ) has attracted significant interest due to its p‐type transport properties and anisotropic lattice structure. Its uniquely narrow bandgap of 0.9–1 eV enables efficient near‐infrared (NIR) detection. However, the growth of large‐area ReSe 2 mostly faces challenges such as the high cost of the precursors and high reaction temperatures incompatible with back‐end‐of‐line (BEOL) processes. This work demonstrates an efficient and low‐cost method to grow large‐area monolayer ReSe 2 at significantly low temperatures (below 450 °C) compatible with BEOL processes, utilizing BiOCl‐assisted Re as a precursor, which is considerably more cost‐effective than the commonly used precursor of ReO 3 . Additionally, the same BiOCl‐assisted low‐temperature growth process has successfully enabled the large‐area growth of monolayer rhenium sulfide (ReS 2 ), demonstrating the versatility of this approach. Comprehensive characterization techniques, including Raman spectroscopy, X‐ray photoelectron spectroscopy, and atomic force microscopy are employed to evaluate the morphology and crystalline quality of the as‐grown monolayer films. The as‐grown centimeter‐scale ReSe 2 has been utilized to fabricate large‐scale, highly uniform near‐infrared detector arrays. Also, the photodetector exhibits an excellent room‐temperature infrared‐imaging capability, providing a solid foundation for the future integration and functionalization of the ReSe 2 in various applications.