Low Frequency Electrical Noise in Single-Layer MoS2 at High Carrier Concentration Encapsulated by Ionic Liquid Gel
Ji-Wun Wang1,2*, Yen-Po Liu2, Bo-Han Chen3, Meng-Hsi Chuang3, Dah-Chin Lin4, Jeng-Chung Chen1, Yi-Hsien Lee3, Yung-Fu Chen2
1Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan
2Department of Physics, National Central University, Jhongli, Taiwan
3Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan
4Department of Physics, Tamkang University, New Taipei, Taiwan
* presenting author:Ji-Wun Wang, email:jiwun.wang@gmail.com
MoS2 monolayers with huge surface-to-bulk ratios are expected to suffer excessive low frequency noise, which is a limiting factor for its applications. Carrier mobility and low frequency noise intensity are affected by the interface of MoS2 surface and gate dielectric material. We report low frequency noise and electrical transport on chemical vapor deposited (CVD) MoS2 monolayers encapsulated by ionic liquid with a gate. Using ionic liquid as gate dielectric, carrier density can be effectively tuned with small range of gate voltage applied but its noise behavior remained unexplored. The noise characteristics of high mobility samples (30–40 cm2/Vs) in both unencapsulated and encapsulated samples show 1/f spectrum and are well described by Hooge empirical law. Hooge parameter α of 0.02 at n ~ 3 × 1012 cm-2 is frequently obtained in samples. The gate dependence studies indicate the measured 1/f noise is dominated by fluctuation of carrier number at high carrier density regime (n ~ 1013 cm-2).

Keywords: MoS2 monolayer, low frequency noise, ionic liquid gel