Strategies on Phase Control in Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) consist of dozens of ultrathin layered materials that have significantly different properties due to their varied phases, which determine the properties and application range of TMDs. Interestingly, a controllable phase transition in TMDs is achieved extensively with the use of several methods. Thus, phase control is a promising way to fully exploit the potential of TMDs. This review introduces the recent rapid development of the study of the TMD phase control, starting from the basic conception of the phase and phase transition in TMDs to the strategies for obtaining phase control. The different strategies are roughly classified into several types based on their characteristics: doping, synthesis method, strain, thermal method, and interlayer coupling. Finally, an evaluation on the prospect of the emergent strategies is provided.