부산대학교 도서관

Recently, 2D Transition Metal Dichalcogenides (TMDCs) have received significant attention in the field of optoelectronics due to their extraordinary optical and electrical properties [1], [2]. Among TMDC family, molybdenum disulfide (MoS 2 ) has intensively been studied. Bulk and monolayer MoS 2 have bandgap energy of ~ 1.3 e V and ~ 1.8 e V, respectively [1], [3]. Different growth techniques such as Atomic Layer Deposition (ALD) are alternatively used aiming at uniform growth of MoS 2 . For ALD Mo and S precursors such as Mo(CO) 6 , MoCl 5 and H 2 S, dimethyl disulfide respectively are used on Si0 2 /Si or sapphire substrate [4]–[7]. Using ALD, the synthesis of wafer scale uniform bilayer MoS 2 film has been reported. However, in the experiment, H 2 S precursor is used both in the reaction cycle [4], [5] and high-temperature post-deposition annealing performed as necessary step to reduce impurity contents and increase crystal quality in the films [6], [7]. H 2 S is highly toxic and has a high vapor pressure at room temperature. As a result, it requires a special container pressure controller and gaskets which increase considerably the cost and risk for use in ALD process. For 2D MoS 2 growth by ALD, uniformly distributed small-size flakes are reported in [4], [5]. In order to control the growth process of 2D MoS 2 , the flake quantity and distribution needs to be taken under control. Interestingly, in CVD, it is possible to grow MoS 2 layer using MoO 3 thin film instead of powder. The control of MoS 2 flake size, density, number of layer and cleanness can be achieved by controlling the MoO 3 thin film. Plasma Enhanced Atomic Layer Deposition technique should be most suitable for such a uniform deposition. Successful growth is reported in [8] but it is not optimized for MoS 2 growth.