Impact of MoS₂ layer transfer on electrostatics of MoS₂/SiO₂ interface

Using internal photoemission of electrons from few-monolayer thin MoS₂ films into SiO₂ we found that the MoS₂ layer transfer processing perturbs electroneutrality of the interface, leading to an increase of the electron barrier height by ≈0.5-1 eV as compared to the case of the same films synthesized directly on SiO₂. This effect is associated with the formation of an interface dipole, tentatively ascribed to interaction of H₂O molecules with the SiO₂ surface resulting in the incorporation of silanol (SiOH) groups. This violation of the interface electroneutrality may account for additional electron scattering in ultrathin transferred films and threshold voltage instabilities. Post-transfer annealing in H₂S is shown to reduce the transfer-induced interface degradation.