  We present a modeling study of a nanopore-based transistor computed by a
mean-field continuum theory (Poisson-Nernst-Planck, PNP) and a hybrid method
including particle simulation (Local Equilibrium Monte Carlo, LEMC) that is
able to take ionic correlations into account including finite size of ions. The
model is composed of three regions along the pore axis with the left and right
regions determining the ionic species that is the main charge carrier, and the
central region tuning the concentration of that species and, thus, the current
flowing through the nanopore. We consider a model of small dimensions with the
pore radius comparable to the Debye-screening length
($R_{\mathrm{pore}}/\lambda_{\mathrm{D}}\approx 1$), which, together with large
surface charges provides a mechanism for creating depletion zones and, thus,
controlling ionic current through the device. We report scaling behavior of the
device as a function the $R_{\mathrm{pore}}/\lambda_{\mathrm{D}}$ parameter.
Qualitative agreement between PNP and LEMC results indicates that mean-field
electrostatic effects determine device behavior to the first order.
