Can somebody explain to me why tungsten diselenide is p-type semiconductor while the other transition metal dichalcogenides are n-type? How are the charge carrier generated in transition metal dichalcogenides?
WSe2 samples may also show n-type doping induced by transport agents in CVT samples such as Br and I. For the p-type doping, excess of Se and the presence of impurities (e.g. V, Ta, Nb, Cr) could explain this conductivity. See: ACS Appl. Mater. Interfaces, 2016, 8 (39), 26400–26406 DOI: 10.1021/acsami.6b08847