Layer Number and Stacking Engineering of MoS₂ Crystals for High-Performance Polarization-Sensitive Photodetector

Abstract

The layer and stacking engineering of two-dimensional (2D) transition-metal dichalcogenides (TMDs) gives rise to novel phenomena and multiapplications; thus, TMDs have garnered considerable attention. However, the precisely customized fabrication of stacked 2D materials to date is largely limited to the lack of effective and controllable growth strategies, prone to the unpredictable stacking orders and randomly distributed nucleation sites. Here, we devise an optimized chemical vapor deposition approach for modulating the MoS 2 single crystals from monolayer to multilayer with diverse stacking configurations. Significantly, the phototransistor based on monolayer MoS 2 single crystal exhibits an ultrasensitive performance with a high photoresponsivity (R) of 3.3 × 10 4 A W −1 and a remarkable detectivity (D*) of above 1.7 × 10 14 Jones at 405 nm light illumination. Ultralow-frequency and angle-resolved polarized Raman spectroscopy is used to systematically uncover the delicate interlayer interactions and crystallographic anisotropy. Moreover, the polarization-sensitive photodetectors using 1−3L MoS 2 show a layer number-dependent anisotropic performance, with dichroism ratios of 1.36, 1.44, and 1.52. This work offers a promising method to not only enable the fabrication of new customized layer-, stacking-, and twist-2D materials but also provides the foundation for the development of advanced polarizationsensitive and optoelectronic devices based on stacking transitions.