Controlled Preparation and Crystal Phase Control of MoTe2 Thin Films by CVD Method

Transition metal cholochide molybdenum telluride (MoTe2) has three crystal phase structures of 2H, Td and 1T', among which 2H phase structure (2H-MoTe2) has attracted much attention due to its small band-gap width (1eV) and high carrier mobility (2500cm2·V-1·s-1). Hexagonal (2H-MoTe2) polycrystals are an indirect gap semiconductor, but refining them into several layers leads to the emergence of a direct band gap of 1.1eV. By comparing the different preparation schemes, as well as the growth preparation methods of other two-dimensional materials, we found that the reactivity of tellurium can be improved by introducing hydrogen, which has the same role in the preparation of other transition metal chalcogenides. In this paper, we successfully prepared two MoTe2 films with different morphologies by chemical vapor deposition. In addition to introducing hydrogen as carrier gas, NaCl was added as catalyst in order to increase the concentration of Mo atoms during the reaction