LAUSR

We report transport measurements of ionic liquid-gated field-effect transistors with multilayer MoS2 channels. Ambipolar characteristics with high ON/OFF ratios (>105) are observed. The current–voltage characteristics agree well with those calculated using a simple model assuming a high recombination probability and negligible contact resistance, except when holes are doped in the vicinity of the source contact. Electron and hole mobilities are estimated using the current–voltage characteristics in both the unipolar and ambipolar modes, wherein a p–n junction is formed in the latter. The electron mobility depends significantly on the carrier distribution in a channel that is controlled by the gate voltage. This result is attributed to the significant field dependence of the electron mobility.