Wednesday, February 2, 2011

Single-layer MoS2 transistors


Nature Nanotechnology
 
(2011)
 
doi:10.1038/nnano.2010.279
Received
 
 
Accepted
 
 
Published online
 

Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene , both because of its rich physics  and its high mobility . However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors7. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS2 have a large intrinsic bandgap of 1.8 eV , previously reported mobilities in the 0.5–3 cm2 V−1 s−1 range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS2 mobility of at least 200 cm2 V−1 s−1, similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on-off ratios of 1 × 108 and ultralow standby power dissipation. Because monolayer MoS2 has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS2could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.

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