Exploration of channel width scaling and edge states in transition metal dichalcogenides
2D-layered materials, edge states, WTe2, MoTe2, MoS2, channel width scaling
ABSTRACT We explore the impact of edge states in three types of transition metal dichalcogenides (TMDs), namely metallic Td-phase WTe2 and semiconducting 2H-phase MoTe2 and MoS2, by patterning thin flakes into ribbons with varying channel widths. No obvious charge depletion at the edges is observed for any of these three materials, in contrast to observations made for graphene nanoribbon devices. The semiconducting ribbons are characterized in a three-terminal field-effect transistor (FET) geometry. In addition, two ribbon array designs have been carefully investigated and found to exhibit current levels higher than those observed for conventional one-channel devices. Our results suggest that device structures incorporating a high number of edges can improve the performance of TMD FETs. This improvement is attributed to a higher local electric field, resulting from the edges, increasing the effective number of charge carriers, and the absence of any detrimental edge-related scattering.
Tsinghua University Press
Feng Zhang,Chia-Hui Lee,Joshua A. Robinson,Joerg Appenzeller, Exploration of channel width scaling and edge states in transition metal dichalcogenides. NanoRes.2018, 11(4): 1768–1774