Gold-vapor-assisted chemical vapor deposition of aligned monolayer WSe 2 with large domain size and fast growth rate

Orientation-controlled growth of two-dimensional (2D) transition metal dichalcogenides (TMDCs) may enable many new electronic and optical applications. However, previous studies reporting aligned growth of WSe 2 usually yielded very small domain sizes. Herein, we introduced gold vapor into the chemical vapor deposition (CVD) process as a catalyst to assist the growth of WSe 2 and successfully achieved highly aligned monolayer WSe 2 triangular flakes grown on c -plane sapphire with large domain sizes (130 µm) and fast growth rate (4.3 µm·s −1 ). When the aligned WSe 2 domains merged together, a continuous monolayer WSe 2 was formed with good uniformity. After transferring to Si/SiO 2 substrates, field effect transistors were fabricated on the continuous monolayer WSe 2 , and an average mobility of 12 cm 2 ·V −1 ·s −1 was achieved, demonstrating the good quality of the material. This report paves the way to study the effect of catalytic metal vapor in the CVD process of TMDCs and contributes a novel approach to realize the growth of aligned TMDC flakes.