Defect passivation of transition metal dichalcogenides via a charge transfer van der Waals interface
Jun Hong Park, Atresh Sanne, Yuzheng Guo, Matin Amani, Kehao Zhang, Hema C. P. Movva, Joshua A. Robinson, Ali Javey, John Robertson, Sanjay K. Banerjee and Andrew C. Kummel
Science Advances 3, e1701661 (2017)
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. 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 the formation of a van der Waals interface, the ION/IOFF in back-gated MoS2 transistors increases by more than two orders of magnitude, whereas the degradation in the photoluminescence signal is suppressed. Density functional theory modeling reveals a van der Waals interaction that allows sufficient charge transfer to remove defect 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.