Quantum-Mechanical Modelling of Charge Transport in Two-Dimensional Materials for Next-Generation Transistor Applications

Background: Two-dimensional materials including graphene, MoS2, and black phosphorus offer transistor channel properties fundamentally superior to silicon at nanometre gate lengths. Quantum-mechanical charge transport modelling tailored to these materials is essential for device engineering at the sub-5 nm scale. Aim: This study developed quantum-mechanical models of charge transport in graphene, MoS2, and black phosphorus 2D transistors and identified optimal channel material and geometry combinations for high-speed and low-power applications. Methods: The non-equilibrium Green's function formalism coupled with density functional theory was implemented using the Nanodcal transport code. Transistors with gate lengths from 5 to 20 nm were simulated. Key performance metrics including on-state current, subthreshold slope, intrinsic switching delay, and power-delay product were extracted and benchmarked against the ITRS roadmap targets. Results: MoS2 transistors with HfO2 high-k gate dielectric achieved near-ideal subthreshold slope of 62 mV/decade at 5 nm gate length. Black phosphorus demonstrated superior hole mobility and balanced ambipolar transport. Graphene nanoribbons required below 3 nm width for adequate on-off current ratios, imposing severe fabrication constraints. Conclusion: MoS2 and black phosphorus are the most viable 2D transistor channel materials for near-term implementation. The developed modelling framework provides a transferable tool for Nigerian semiconductor research groups. Keywords: 2D materials, transistor, quantum transport, NEGF, MoS2.