Enhanced sulfurization reaction of molybdenum using a thermal cracker for forming two-dimensional MoS2 layers
| Autor: | Won Seok Han, Dae-Hyung Cho, Jae-Hyung Wi, Woo-Jung Lee, Byungha Shin, Sun Jin Yun, Yong-Duck Chung |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
General Physics and Astronomy chemistry.chemical_element 02 engineering and technology Substrate (electronics) Thermal treatment Chemical vapor deposition 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound chemistry Chemical engineering Sputtering Molybdenum Phase (matter) Physical and Theoretical Chemistry 0210 nano-technology Molybdenum disulfide Layer (electronics) |
| Zdroj: | Physical Chemistry Chemical Physics. 20:16193-16201 |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | We propose a method to fabricate two-dimensional (2D) molybdenum disulfide (MoS2) layers to overcome issues in typical fabrication processes by promoting the sulfurization reaction of molybdenum (Mo). A thin sputtered-Mo layer was sulfurized using a sulfur (S) thermal cracker to form 2D MoS2 layers. The effects of key process parameters such as cracking-zone temperature (TC-zone), thickness of the sputtered-Mo layer, and Ar pressure during deposition of the Mo layer were systematically investigated. The degree of thermal treatment of evaporated S vapor is controlled by varying TC-zone. The higher TC-zone enabled easy formation of thin MoS2 layers at a low substrate temperature of 250 °C due to the greatly enhanced sulfurization reaction. The thickness of the final MoS2 layers was controlled by changing the initial thickness of the sputtered-Mo film. Ultra-thin MoS2 film about 2-layers-thick was obtained by sulfurizing a 2 A-thick Mo film. The chemical state of the MoS2 layers largely depended on the Ar pressure during the sputtering process of the initial Mo. Lower Ar pressure enhanced MoS2 formation due to more efficient substitution of the MoS2 phase for the MoO3 phase. By using the S thermal cracker, we demonstrate a method to easily fabricate 2D MoS2 layers, excluding some problematic issues such as toxic and expensive reactants, non-vacuum conditions susceptible to contamination, and high substrate temperature. |
| Databáze: | OpenAIRE |
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