Functional group-induced p-doping of MoS2 by titanium(IV) bis(ammonium lactato) dihydroxide physisorption.

P-type doping is of critical importance for the realization of certain high performance electrical and optoelectronic devices based on molybdenum disulfide (MoS 2 ). The charge transfer doping is a feasible strategy for tuning the conductance properties via facile treatment. In this work, the electrical properties of few-layer MoS 2 were modulated with titanium(IV) bis(ammonium lactato) dihydroxide molecules (denoted as TALH) via physisorption. The functional groups such as electronegative hydroxyl (-OH) and carboxylate group (-COO) included in TALH molecules are expected to induce p-doping effect through surface charge transfer when being attached to MoS 2 . The p-doping is proved by X-ray photoelectron spectroscopy (XPS) with the downshift of Mo 3d and S 2p peaks. Control experiments and density functional theory calculations validate that the p-type doping mainly originated from the -OH group in TALH, which drew electrons from MoS 2 . These results suggest that functional group-mediated p-doping effect show a path to modulate the carrier transition in MoS 2, and enrich the molecule series for device modification.