13:30 〜 13:45
▲ [19p-E308-2] Chemical Vapor Deposition of 2D Transition Metal Dichalcogenides – Just Add Salts
キーワード：2D materials, chemical vapor deposition, vapor-liquid-solid
Chemical vapor deposition (CVD) of 2D transition-metal dichalcogenides (TMDCs) usually involves the conversion of vapor precursors into solid products via a vapor-solid-solid (VSS) mode (WO3 + S/Se + H2 → WS2/WSe2). It always requires an extremely high temperature and low pressure to sublimate the transition metal oxides.
In 2015, we published a pioneering work on halide-assisted atmospheric-pressure CVD of WSe2 and WS2 monolayers at lower temperature due to the formation of volatile tungsten oxychlorides (WO3 + NaCl → WOxCly, WOxCly + S/Se + H2 → WS2/WSe2).[1,2] This method has been widely used for growing ~ 50 types of 2D TMDCs in the last four years.[3]
In 2018, we revealed the important vapor-liquid-solid (VLS) growth of TMDCs which is triggered by the alkali cations in salt-assisted CVD (MoO3 + NaCl → Na2MoxOy, Na2MoxOy + S → MoS2). The in-situ generated non-volatile Na-Mo-O droplets mediate the growth of 1D MoS2 nanoribbons on NaCl crystal and 2D MoS2 film.[4]
The VLS growth involves non-volatile molten precursors (e.g., Na2MoO4, Na2WO4) shows great advantages in wafer-scale growth of 2D TMDC film and patterned (site-controlled) growth of 2D TMDC monolayers.[5] We clarified that the VLS growth thus pave the new way for the high-efficient, scalable synthesis of two-dimensional TMDC monolayers. It opens a new research direction for the 2D community.
References
S. Li, et al, Appl. Mater. Today 1 (2015), 60-66
D. Bradley, Mater. Today 18 (2015), 533
J. Zhou, et al, Nature 556 (2018), 355-359
S. Li,* et al, Nat. Mater. 17 (2018), 535-542
S. Li,* et al, submitted
In 2015, we published a pioneering work on halide-assisted atmospheric-pressure CVD of WSe2 and WS2 monolayers at lower temperature due to the formation of volatile tungsten oxychlorides (WO3 + NaCl → WOxCly, WOxCly + S/Se + H2 → WS2/WSe2).[1,2] This method has been widely used for growing ~ 50 types of 2D TMDCs in the last four years.[3]
In 2018, we revealed the important vapor-liquid-solid (VLS) growth of TMDCs which is triggered by the alkali cations in salt-assisted CVD (MoO3 + NaCl → Na2MoxOy, Na2MoxOy + S → MoS2). The in-situ generated non-volatile Na-Mo-O droplets mediate the growth of 1D MoS2 nanoribbons on NaCl crystal and 2D MoS2 film.[4]
The VLS growth involves non-volatile molten precursors (e.g., Na2MoO4, Na2WO4) shows great advantages in wafer-scale growth of 2D TMDC film and patterned (site-controlled) growth of 2D TMDC monolayers.[5] We clarified that the VLS growth thus pave the new way for the high-efficient, scalable synthesis of two-dimensional TMDC monolayers. It opens a new research direction for the 2D community.
References
S. Li, et al, Appl. Mater. Today 1 (2015), 60-66
D. Bradley, Mater. Today 18 (2015), 533
J. Zhou, et al, Nature 556 (2018), 355-359
S. Li,* et al, Nat. Mater. 17 (2018), 535-542
S. Li,* et al, submitted