Versatile and scalable chemical vapor deposition of vertically aligned MoTe₂ on reusable Mo foils

Layered MoTe₂ has shown great promises for optoelectronics and energy-storage applications due to its exceptional optical and electrochemical properties. To date, considerable efforts have been devoted to fabricating layered MoTe₂ with lateral orientation by means of mechanical/chemical exfoliation and chemical vapor deposition (CVD) methods. As compared to its horizontal counterparts, vertically aligned MoTe₂ with higher density of active edge sites is expected to possess unique optoelectronic and electrochemical properties, while which has not been reported yet. In this work, we report a versatile and scalable CVD growth of vertically aligned MoTe₂ with length of up to ~ 7.5 µm on Mo foil. Remarkably, the dominant phase of the vertically aligned MoTe₂ can be tuned from 2H to 1T’ by increasing the growth temperature from 630 to 780 °C. Owing to the weak interaction between the as-grown MoTe₂ and Mo foil, the as-grown MoTe₂ can be easily detached from the Mo foil. This in turn enabled economic reuse of the Mo foil for multiple growth. Moreover, the vertical growth of the MoTe₂ is proposed to be caused by the internal strain generated during tellurization of Mo foil. Furthermore, the as-grown MoTe₂ can also be directly dispersed in solvent to produce high-quality MoTe₂ nanosheets. The versatility of this growth strategy was further demonstrated by fabricating other vertically aligned transition metal chalcogenides (TMDs) such as TaTe₂ and MoSe₂. Hence, this work paves the path towards achieving unique TMDs structures to enable high-performance optoelectronic and electrochemical devices.