Defect Etching of Phase-Transition-Assisted CVD-Grown 2H-MoTe2.

Abstract

2D molybdenum ditelluride (MoTe2 ) with polymorphism is a promising candidate to developing phase-change memory, high-performance transistors and spintronic devices. The phase-transition-assisted chemical vapor deposition (CVD) process has been used to prepare large-scale 2H-MoTe2 with large grain size and low density of grain boundary. However, because of the lack of precise control of the growth condition, some defects including the amorphous regions and grain boundaries in 2H-MoTe2 are hardly avoidable. Here, a facile method of selectively etching defects in large-scale CVD-grown 2H-MoTe2 by triiodide ion (I3 - ) solution is reported. The defect etching is attributed to the reduced lattice symmetry, high chemisorption activity and high conductivity of the defects due to the high density of Te vacancies. The treated 2H-MoTe2 shows the suppressed hysteresis in the electrical transfer curve, enhances hole mobility and the higher effective barrier height on the metal contact, suggesting the decreased density of defects. Further chemical analysis indicates that the 2H-MoTe2 is not damaged or doped by I3 - solution during the etching process. This simple and low-cost post-processing method is effective for etching the defects in large-area 2H-MoTe2 for high-performance device applications.