09:15 〜 09:30
▲ [14a-213-2] Synthesis of Molybdenum Disulfide Ribbons by Chemical Vapor Deposition in Sulfur Enriched Condition
キーワード：MoS2, Ribbons, Semiconductor
Monolayer transition metal dichalcogenides (TMDCs) are the emerging class of two dimensional direct band gap semiconductors for future nanoelectronic, optoelectronic and catalytic applications. The chemical vapor deposition (CVD) technique has been explored for synthesis of uniform and high quality molybdenum disulfide (MoS2) and other TMDCs. TMDCs monolayer ribbons are also of significant interest owing to its unique properties, however the growth of ribbon is quite challenging than the other crystals [1]. Here, we demonstrate an approach to synthesize MoS2 ribbons and their branched structures.
The MoS2 ribbons were grown by a CVD method on SiO2/Si substrate with optimized experimental parameters. The synthesis was executed in two individually controlled quartz tube furnaces using argon (97%) and hydrogen (3%) gas mixture at atmospheric pressure. The sulfur (1 gm) boat and MoO3 (0.01 gm) boat were placed inside the CVD quartz tube. SiO2/Si substrate was kept face down on the MoO3 powder holding boat, where the substrate position significantly influence the morphology of the MoS2 crystals.
Figure 1 shows scanning electron microscope (SEM) analysis of the MoS2 ribbons, branches and edge structures. Interestingly, all the ribbons possess uneven edge structures, where the edges are formed with angles of 60° and 120°, indicating variation in molybdenum and sulfur edge terminations. The growth of ribbons can be explained by surface diffusion limited process with low concentration of MoO3 and enriched sulfur concentration [2, 3]. In the CVD process, the directional growth of the MoS2 ribbon is achieved in presence of very low concentration of molybdenum precursor on the SiO2/Si substrate surface.
The MoS2 ribbons were grown by a CVD method on SiO2/Si substrate with optimized experimental parameters. The synthesis was executed in two individually controlled quartz tube furnaces using argon (97%) and hydrogen (3%) gas mixture at atmospheric pressure. The sulfur (1 gm) boat and MoO3 (0.01 gm) boat were placed inside the CVD quartz tube. SiO2/Si substrate was kept face down on the MoO3 powder holding boat, where the substrate position significantly influence the morphology of the MoS2 crystals.
Figure 1 shows scanning electron microscope (SEM) analysis of the MoS2 ribbons, branches and edge structures. Interestingly, all the ribbons possess uneven edge structures, where the edges are formed with angles of 60° and 120°, indicating variation in molybdenum and sulfur edge terminations. The growth of ribbons can be explained by surface diffusion limited process with low concentration of MoO3 and enriched sulfur concentration [2, 3]. In the CVD process, the directional growth of the MoS2 ribbon is achieved in presence of very low concentration of molybdenum precursor on the SiO2/Si substrate surface.