Center for Functional Nanomaterials Seminar

Atomically thin two-dimensional (2D) semiconductors—particularly transition metal dichalcogenides (TMDCs)—have emerged as promising channel materials for post-silicon complementary metal–oxide–semiconductor (CMOS) field-effect transistors (FETs). However, achieving nondestructive, impurity-free doping and low contact resistance remains a critical challenge limiting their performance and scalability. In this talk, I will present a multiscale strategy to overcome these bottlenecks, focusing on nanoscale doping and contact engineering. First, I will introduce a remote charge-transfer doping method using a hexagonal boron nitride (hBN) as a spacer between MoS2 and molecular dopants. This approach significantly suppresses charged impurity scattering and enhances field-effect mobility by over 200%, offering a pathway toward high-mobility 2D electronics. Next, I will talk about a diffusion doping strategy for large-area, CVD-grown monolayer MoS2. By selectively depositing dopants only on the contact regions via inkjet printing, excess electrons diffuse into the channel due to the carrier density gradient. This approach effectively mitigates charged impurity scattering and achieves more than twofold improvement in mobility compared to conventional direct doping. Finally, I will briefly highlight two ongoing projects aimed at CMOS-compatible integration: (1) Inorganic remote modulation doping enabled by oxygen plasma-induced defect engineering, and (2) semimetal contact engineering to suppress metal-induced gap states (MIGS) and reduce Fermi-level pinning. These efforts push toward a robust, scalable doping and contact platform for next-generation 2D electronics.