Tuning Electrical Conductance in Bilayer MoS through Defect-Mediated Interlayer Chemical Bonding.

Interlayer interaction could substantially affect the electrical transport in transition metal dichalcogenides, serving as an effective way to control the device performance. However, it is still challenging to utilize interlayer interaction in weakly interlayer-coupled materials such as pristine MoS to realize layer-dependent tunable transport behavior. Here, we demonstrate that, by substitutional doping of vanadium atoms in the Mo sites of the MoS lattice, the vanadium-doped monolayer MoS device exhibits an ambipolar field effect characteristic, while its bilayer device demonstrates a heavy -type field effect feature, in sharp contrast to the pristine monolayer and bilayer MoS devices, both of which show similar -type electrical transport behaviors. Moreover, the electrical conductance of the doped bilayer MoS device is drastically enhanced with respect to that of the doped monolayer MoS device. Employing first-principle calculations, we reveal that such striking behaviors arise from the presence of electrical transport networks associated with the enhanced interlayer hybridization of S-3p orbitals between adjacent layers activated by vanadium dopants in the bilayer MoS, which is nevertheless absent in its monolayer counterpart. Our work highlights that the effect of dopant not only is confined in the in-plane electrical transport behavior but also could be used to activate out-of-plane interaction between adjacent layers in tailoring the electrical transport of the bilayer transitional metal dichalcogenides, which may bring different applications in electronic and optoelectronic devices.