  The electrostatics of two-dimensional (2D) lateral pn homojunctions
considering the impact of electrostatic doping by means of two split
bottom-gates are studied here. Analytical expressions are obtained from the
solution of the 2D Poisson equation considering a depletion approximation.
Straightforward analytical models for the electrostatic potential and the
depletion width within both the dielectric and the 2D semiconductor are
obtained for both the symmetrical and asymmetrical cases. In contrast to the
case of devices with chemical doping, the obtained depletion width model of
devices with electrostatic doping do not depend on the dielectric constant but
only on the electrostatic potential and oxide thickness. The models describe
the electrostatics of gate-tunable 2D pn junctions at arbitrary bias. A
benchmark against numerical device simulations of MoS2-based pn junctions
validate the analytical models.
