Multi-valley high-field transport in 2-dimensional MoS2 transistors

In this study we investigate for the first time both low-and high-field transport in few-layer MoS2 transistors using a two-valley band structure [Fig. 1], by combining simulations and experimental data [5]. We find that taking into account both the K and Q conduction band valley (with the Q valley along K to Γ being ΔE ≈ 0.13 eV higher) is necessary in order to understand all transport regimes. This finding clarifies the results of several theoretical band structure studies [6-8], which until now showed disagreement about this inter-valley separation. We demonstrate that a two-valley band structure and device self-heating should be taken into account to understand a wide range of transport in MoS2 transistors. Our results also help clarify the band structure of MoS2 as relevant for a variety of applications. This work was supported in part by NSF and STARnet/SONIC.