Layer Number and\nStacking Engineering of MoS<sub>2</sub> Crystals for High-Performance\nPolarization-Sensitive Photodetector

The layer and stacking engineering of two-dimensional\n(2D) transition-metal\ndichalcogenides (TMDs) gives rise to novel phenomena and multiapplications;\nthus, TMDs have garnered considerable attention. However, the precisely\ncustomized fabrication of stacked 2D materials to date is largely\nlimited to the lack of effective and controllable growth strategies,\nprone to the unpredictable stacking orders and randomly distributed\nnucleation sites. Here, we devise an optimized chemical vapor deposition\napproach for modulating the MoS<sub>2</sub> single crystals from monolayer\nto multilayer with diverse stacking configurations. Significantly,\nthe phototransistor based on monolayer MoS<sub>2</sub> single crystal\nexhibits an ultrasensitive performance with a high photoresponsivity\n(<i>R</i>) of 3.3 × 10<sup>4</sup> A W<sup>−1</sup> and a remarkable detectivity (<i>D*</i>) of above 1.7\n× 10<sup>14</sup> Jones at 405 nm light illumination. Ultralow-frequency\nand angle-resolved polarized Raman spectroscopy is used to systematically\nuncover the delicate interlayer interactions and crystallographic\nanisotropy. Moreover, the polarization-sensitive photodetectors using\n1–3L MoS<sub>2</sub> show a layer number-dependent anisotropic\nperformance, with dichroism ratios of 1.36, 1.44, and 1.52. This work\noffers a promising method to not only enable the fabrication of new\ncustomized layer-, stacking-, and twist-2D materials but also provides\nthe foundation for the development of advanced polarization-sensitive\nand optoelectronic devices based on stacking transitions.