Combined electrical transport and capacitance spectroscopy of a ${\mathrm{MoS_2-LiNbO_3}}$ field effect transistor

W. Michailow, F. J. R. Schülein, B. Möller, E. Preciado, A. E. Nguyen, G. v. Son, J. Mann, A. L. Hörner, A. Wixforth, L. Bartels, H. J. Krenner

Published 2017-01-02Version 1

We have measured both the current-voltage ($I_\mathrm{SD}$-$V_\mathrm{GS}$) and capacitance-voltage ($C$-$V_\mathrm{GS}$) characteristics of a $\mathrm{MoS_2-LiNbO_3}$ field effect transistor. From the measured capacitance we calculate the electron surface density and show that its gate voltage dependence follows the theoretical prediction resulting from the two-dimensional free electron model. This model allows us to fit the measured $I_\mathrm{SD}$-$V_\mathrm{GS}$ characteristics over the \emph{entire range} of $V_\mathrm{GS}$. Combining this experimental result with the measured current-voltage characteristics, we determine the field effect mobility as a function of gate voltage. We show that for our device this improved combined approach yields significantly smaller values (more than a factor of 4) of the electron mobility than the conventional analysis of the current-voltage characteristics only.