Enhanced performance of multilayer MoS2 transistors encapsulated with a photoresist

We report the enhanced performance of multilayer MoS2 transistors by AZ(R) 5214E photoresist encapsulation. The MoS2 transistors with SiO2 bottom-gate dielectrics exhibited an average increase of 4x in the on/off-current ratio and a 50% increase in the field-effect mobility after photoresist encapsulation. The Y-function method further showed a decrease of 87% in the contact resistance and a 30% increase in the intrinsic carrier mobility, suggesting that photoresist encapsulation provides not only n-type doping but also dielectric screening. The Raman spectra of the photoresist-encapsulated MoS2 also suggest n-type doping, which may be due to the electropositive hydroxyl groups in the photoresist. The operation of the photoresist-encapsulated MoS2 transistors remained stable in ambient air for at least one month. These results demonstrate that simple photoresist encapsulation can be an effective performance booster of MoS2 and other transition metal dichalcogenides transistors.