Low Ohmic contact resistance and high on/off ratio in transition metal dichalcogenides field-effect transistors via residue-free transfer

Beyond-silicon technology demands ultrahigh performance field-effect transistors. Transition metal dichalcogenides provide an ideal material platform, but the device performances such as the contact resistance, on/off ratio and mobility are often limited by the presence of interfacial residues caused by transfer procedures. Here, we show an ideal residue-free transfer approach using polypropylene carbonate with a negligible residue coverage of similar to 0.08% for monolayer MoS2 at the centimetre scale. By incorporating a bismuth semimetal contact with an atomically clean monolayer MoS2 field-effect transistor on hexagonal boron nitride substrate, we obtain an ultralow Ohmic contact resistance of similar to 78 Omega mu m, approaching the quantum limit, and a record-high on/off ratio of similar to 10(11) at 15 K. Such an ultra-clean fabrication approach could be the ideal platform for high-performance electrical devices using large-area semiconducting transition metal dichalcogenides.

Automated summary

Researchers have developed a residue-free transfer method using polypropylene carbonate to transfer monolayer MoS2 onto a hexagonal boron nitride substrate at the centimetre scale. By incorporating a bismuth semimetal contact with an atomically clean monolayer MoS2 field-effect transistor, they achieved an ultralow Ohmic contact resistance and a record-high on/off ratio, making it an ideal platform for high-performance electrical devices using large-area transition metal dichalcogenides.