Abstract

We develop an oxygen-free fabrication approach for two-dimensional TMD field-effect transistors and show that avoiding ambient oxygen exposure substantially improves transport. Density functional theory indicates that O₂ can chemisorb strongly at sulfur vacancies in MoS₂ and WS2, leading to irreversible p-doping, whereas N₂ and H₂O mostly physisorb. Experimentally, inert-processed devices show more than an order-of-magnitude enhancement in carrier mobility, sheet conductance, carrier density, and on/off ratio, with record room-temperature mobilities of 91 cm2 V-1 s-1 for monolayer MoS₂ and 132 cm2 V-1 s-1 for bilayer MoS₂ on SiO2.

Abstract

We develop an oxygen-free fabrication approach for two-dimensional TMD field-effect transistors and show that avoiding ambient oxygen exposure substantially improves transport. Density functional theory indicates that O₂ can chemisorb strongly at sulfur vacancies in MoS₂ and WS2, leading to irreversible p-doping, whereas N₂ and H₂O mostly physisorb. Experimentally, inert-processed devices show more than an order-of-magnitude enhancement in carrier mobility, sheet conductance, carrier density, and on/off ratio, with record room-temperature mobilities of 91 cm2 V-1 s-1 for monolayer MoS₂ and 132 cm2 V-1 s-1 for bilayer MoS₂ on SiO2.

Abstract

We develop an oxygen-free fabrication approach for two-dimensional TMD field-effect transistors and show that avoiding ambient oxygen exposure substantially improves transport. Density functional theory indicates that O₂ can chemisorb strongly at sulfur vacancies in MoS₂ and WS2, leading to irreversible p-doping, whereas N₂ and H₂O mostly physisorb. Experimentally, inert-processed devices show more than an order-of-magnitude enhancement in carrier mobility, sheet conductance, carrier density, and on/off ratio, with record room-temperature mobilities of 91 cm2 V-1 s-1 for monolayer MoS₂ and 132 cm2 V-1 s-1 for bilayer MoS₂ on SiO2.

Abstract

We develop an oxygen-free fabrication approach for two-dimensional TMD field-effect transistors and show that avoiding ambient oxygen exposure substantially improves transport. Density functional theory indicates that O₂ can chemisorb strongly at sulfur vacancies in MoS₂ and WS2, leading to irreversible p-doping, whereas N₂ and H₂O mostly physisorb. Experimentally, inert-processed devices show more than an order-of-magnitude enhancement in carrier mobility, sheet conductance, carrier density, and on/off ratio, with record room-temperature mobilities of 91 cm2 V-1 s-1 for monolayer MoS₂ and 132 cm2 V-1 s-1 for bilayer MoS₂ on SiO2.