Single-layer MoS2 transistors

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^1,2, both because of its rich physics^3,4,5 and its high mobility⁶. 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^{8,9,10,11,12,13} or requires high voltages^14,15. Although single layers of MoS₂ have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5–3 cm² V^‑1 s^‑1 range¹⁷ 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^16,18, it can be used to construct interband tunnel FETs¹⁹, which offer lower power consumption than classical transistors. Monolayer MoS₂ could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.