Phase‐Controlled Growth of 1T′‐MoS₂ Nanoribbons on 1H‐MoS₂ Nanosheets

2D heterostructures are emerging as alternatives to conventional semiconductors, such as silicon, germanium, and gallium nitride, for next-generation electronics and optoelectronics. However, the direct growth of 2D heterostructures, especially for those with metastable phases still remains challenging. To obtain 2D transition metal dichalcogenides (TMDs) with designed phases, it is highly desired to develop phase-controlled synthetic strategies. Here, a facile chemical vapor deposition method is reported to prepare vertical 1H/1T' MoS₂ heterophase structures. By simply changing the growth atmosphere, semimetallic 1T'-MoS₂ can be in situ grown on the top of semiconducting 1H-MoS₂, forming vertical semiconductor/semimetal 1H/1T' heterophase structures with a sharp interface. The integrated device based on the 1H/1T' MoS₂ heterophase structure displays a typical rectifying behavior with a current rectifying ratio of ≈10³. Moreover, the 1H/1T' MoS₂-based photodetector achieves a responsivity of 1.07 A W^-1 at 532 nm with an ultralow dark current of less than 10^-11 A. The aforementioned results indicate that 1H/1T' MoS₂ heterophase structures can be a promising candidate for future rectifiers and photodetectors. Importantly, the approach may pave the way toward tailoring the phases of TMDs, which can help us utilize phase engineering strategies to promote the performance of electronic devices.