  We report a configuration strategy for improving the thermoelectric (TE)
performance of two-dimensional (2D) transition metal dichalcogenide (TMDC) WS2
based on the experimentally prepared WS2/WSe2 lateral superlattice (LS)
crystal. On the basis of density function theory combined with Boltzmann
transport equation, we show that the TE figure of merit zT of monolayer WS2 is
remarkably enhanced when forming into a WS2/WSe2 LS crystal. This is primarily
ascribed to the almost halved lattice thermal conductivity due to the enhanced
anharmonic processes. Electronic transport properties parallel (xx) and
perpendicular (yy) to the superlattice period are highly symmetric for both p-
and n-doped LS owing to the nearly isotropic lifetime of charger carriers. The
spin-orbital effect causes a significant split of conduction band and leads to
three-fold degenerate sub-bands and high density of states (DOS), which offers
opportunity to obtain the high n-type Seebeck coefficient (S). Interestingly,
the separated degenerate sub-bands and upper conduction band in monolayer WS2
form a remarkable stairlike DOS, yielding a higher S. The hole carriers with
much higher mobility than electrons reveal the high p-type power factor and the
potential to be good p-type TE materials with optimal zT exceeds 1 at 400K in
WS2/WSe2 LS.
