Strain-Controlled Interfacial Transport Governs Contact Resistance in Top and Edge n/p-Type Metal-TMD Junctions

Contact resistance at two-dimensional (2D) metal-semiconductor interfaces remains a key bottleneck limiting transition-metal dichalcogenide (TMD) transistor performance. Strain engineering can reduce contact resistance, yet a predictive framework linking strain-induced electronic structure changes to interfacial carrier injection remains lacking. Here, we develop a multiscale framework combining first-principles calculations with analytical transport models to quantify strain-dependent contact resistance in metal-TMD junctions. We investigate n-type Au/MoS2 and p-type Pd/WSe2 contacts in top and edge geometries within experimentally accessible strain ranging from -1 to +1%. Tensile strain reduces n-type contact resistance by up to 46%/%ε, whereas compressive strain lowers p-type resistance by up to 34%/%ε. Edge contacts outperform top contacts by ∼2× due to direct interfacial hybridization. Under optimal strain and doping, room-temperature contact resistance reaches 0.32-0.74 and 0.51-0.84 kΩ·μm for Au/MoS2 and Pd/WSe2, respectively. These results quantitatively agree with experiments and benchmarks across alternative metal contacts, establishing a predictive framework for ultralow-resistance 2D-TMD transistors.