1/F Noise in MoS2 Field Effect Transistors with Channel Length Variation

Field effect transistors (FETs) based on emerging nanoscale channel materials have numerous applications including post-CMOS logic for digital computing, communication and biochemical sensing. However, in fundamental level each of these applications requires tight scrutiny of carrier transport as the device operates in the desired regime and in the proposed environment. One of the important characteristics is to analyze the 1/f noise spectroscopy of the electronic device. In this paper we fabricate multilayer (15 atomic layer) MoS₂ transistors of two different channel lengths (1µm and 2µm) and study the flicker noise in the devices at room temperature and ambient conditions; both devices being fabricated following the same process flows on a single micro-mechanically exfoliated flake of MoS₂; thereby eliminating variability of 1/f noise from fabrication standpoints. Channel dominated 1/f noise with Hooge’s mobility fluctuation model for the devices were extracted from the bias dependent noise spectra. The noise characteristics of the devices are stable over several months of exposure to ambient. The robustness of the channel to its ambient and stability of current fluctuations reveal MoS₂as an emerging candidate for reliable sensing.

Figure shows 1/f noise spectra of MoS₂ FET with 15 atomic layer thick back-gated channels with Cr/Au source and drain electrodes. Channel lengths of 1µm and 2µm were compared for this study.   

Key words: 1/f noise, MoS₂ FETs, biochemical sensing