Defect Passivation of Transition Metal Dichalcogenides via a Charge Transfer Van-der-Waals Interface
Integration of transition metal dichalcogenides (TMDs) into next generation semiconductor platforms has been limited due to a lack of effective passivation techniques for defects in TMDs. Here, the formation of an organic-inorganic van-der-Waals interface between a monolayer (ML) of titanyl phthalocyanine (TiOPc) and a ML of MoS2 is investigated as a defect passivation method. A strong negative charge transfer from MoS2 to TiOPc molecules is observed in scanning tunneling microscopy. As a result of a formation of a van-der-Waals interface, the ION/IOFF in back-gated MoS2 transistors increases by more than two orders of magnitude, while degradation in the photoluminescence signal is suppressed. Density functional theory modeling reveals a van der Waals interaction allowing sufficient charge transfer to remove defects states in MoS2. The present organic-TMD interface is a model system to control the surface/interface states in TMDs by using charge transfer to a Van der Waals bonded complex.