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Effect of High-(KAPPA) Dielectric Passivation on Electrical Transport and Low-Frequency Noise in Single-Layer MoS_(2) Devices



Deepak K. Sharma, Matin Amani, Abhishek Motayed, Pankaj B. Shah, A. Glen Birdwell , Sina Najmaei, Pulickel M. Ajayan, Jun Lou, Madan Dubey, Qiliang Li, Albert Davydov


We have studied temperature-dependent (300K to 77K) electrical characteristics and low-frequency noise (LFN) in chemical vapor deposited (CVD) single layer molybdenum disulfide MoS_(2) based back-gated field-effect transistors (FETs). Electrical characterization and LFN measurements were conducted on MoS_(2) FETs with Al_(2)O_(3) top-surface passivation, and after removal of the passivation. Significant decrease in channel current and transconductance was observed in these devices after Al_(2)O_(3) passivation was etched. For passivated devices, the two-terminal resistance variation with temperature showed good fit to the activation energy model, whereas for the unpassivated devices the trend indicated a hoping transport mechanism. A significant increase in the normalized drain current noise power spectral density (PSD) was observed with the removal of the passivation layer. The observed channel current noise was explained using standard unified model incorporating carrier number fluctuation and correlated surface mobility fluctuation mechanisms. Detailed analysis of the gate-referred noise voltage PSD indicated the presence of different trapping states in passivated devices when compared to the unpassivated devices. Unpassivated devices showed weak temperature-dependence of the channel current noise, whereas passivated devices exhibited near-linear temperature-dependence. This is the first report on noise measurements on CVD grown single-layer MoS_(2) FETs.
ACS Nano


Sharma, D. , Amani, M. , Motayed, A. , Shah, P. , , A. , Najmaei, S. , M., P. , Lou, J. , Dubey, M. , Li, Q. and Davydov, A. (2014), Effect of High-(KAPPA) Dielectric Passivation on Electrical Transport and Low-Frequency Noise in Single-Layer MoS_(2) Devices, ACS Nano (Accessed July 13, 2024)


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Created March 18, 2014, Updated February 21, 2020