Robust epitaxy of single-crystal transition-metal dichalcogenides on lanthanum-passivated sapphire

Two-dimensional (2D) transition-metal dichalcogenide (TMDC) semiconductors are promising materials for beyond-silicon electronics, but the growth of single-crystalline TMDCs has been limited to small wafer sizes in laboratory settings. We report the epitaxy of 150-millimeter single-crystalline TMDC wafers on lanthanum-passivated c -plane sapphire. The single atomic layer of lanthanum reduces the surface symmetry and increases the energy difference between antiparallel domains by as much as 200 times, leading to unidirectional domain alignment. We grew single-crystalline molybdenum disulfide (MoS 2 ), molybdenum diselenide (MoSe 2 ), tungsten disulfide (WS 2 ), and tungsten diselenide (WSe 2 ) by means of both chemical vapor deposition (CVD) and metal-organic CVD processes. Wafer-scale spectroscopies and device measurements demonstrate the exceptional quality and uniformity of 150-millimeter TMDCs, with average mobility of 110 and 131 square centimeters per volt per second for MoS 2 and WSe 2 , respectively, at room temperature.