The effect of the stacking arrangement on the device behavior of bilayer MoS₂ FETs

The effect of three different interlayer stacking arrangements of bilayer (BL) molybdenum disulfide (MoS₂) channel material on the device behavior of p- and n-metal–oxide–semiconductor field-effect transistors (MOSFETs) is extensively investigated using first-principles calculation based on density functional theory, emphasizing electronic properties such as the eigenstates, effective mass, band structure, and total energy of the BL-MoS₂ for various stacking arrangements. The corresponding effects on the MOSFET device characteristics are then analyzed. The results indicate that the hole effective masses in both the longitudinal (transport) and transverse direction are highly sensitive to the interlayer stacking arrangement, and the performance of the p-MOSFET can be significantly tuned for a suitable stacking configuration of the BL-MoS₂. Indeed, 24.12% and 31.37% improvements in the on-state current and transconductance are observed, respectively, for the p-MOSFET compared with the natural stacking arrangement of BL-MoS₂. The ballistic BL-MoS₂-based p- and n-MOSFETs with the tuned stacking arrangement demonstrate an on-state current on the order of 10³ µA/µm along with an on-state/off-state current ratio greater than 10³, a near-ideal (> 65 mV/decade) subthreshold swing, and small (< 30 mV/V) drain-induced barrier lowering effects.