Observation of localized states in atomically thin MoS₂ field effect transistor

Abstract

We present electrical transport and low frequency (1/f) noise measurements on mechanically exfoliated single, bi and trilayer MoS₂ -based FET devices on Si/SiO₂ substrate. We find that the electronic states in MoS₂ are localized at low temperatures (T) and conduction happens through Variable Range Hopping (VRH). A steep increase of 1/f noise with decreasing T, typical for localized regime was observed in all of our devices. From gate voltage dependence of noise, we find that the noise power is inversely proportional to square of the number density (∝ 1/n²) for a wide range of T, indicating number density fluctuations to be the dominant source of 1/f noise in these MoS₂ FETs.