Monolayer transition metal dichalcogenides (TMDCs) with high crystalline quality are important channel materials for next-generation electronics. Researches on TMDCs have been accelerated by the development of chemical vapor deposition (CVD). However, antiparallel domains and twin grain boundaries (GBs) usually form in CVD synthesis due to the special threefold symmetry of TMDCs lattices. The existence of GBs severely reduces the electrical and photoelectrical properties of TMDCs, thus restricting their practical applications. Herein, the epitaxial growth of single crystal MoS2 (SC-MoS2 ) monolayer is reported on Au (111) film across a two-inch c-plane sapphire wafer by CVD. The MoS2 domains obtained on Au (111) film exhibit unidirectional alignment with zigzag edges parallel to the <110> direction of Au (111). Experimental results indicated that the unidirectional growth of MoS2 domains on Au (111) is a temperature-guided epitaxial growth mode. The high growth temperature provides enough energy for the rotation of the MoS2 seeds to find the most favorable orientation on Au (111) to achieve a unidirectional ratio of over 99%. Moreover, the unidirectional MoS2 domains seamlessly stitched into single crystal monolayer without GBs formation. The progress achieved in this work will promote the practical applications of TMDCs in microelectronics.
Keywords: chemical vapor deposition; epitaxy; molybdenum disulfide; single crystal; unidirectional alignment.
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