PdSe ₂ /WSe ₂ Nanosheet-Based Heterostructures for n-Type Field-Effect Transistors with Enhanced Performance

Two-dimensional (2D) semiconductors are promising candidates for next-generation flexible electronics, but their performance is often limited by low electron mobility and substantial Schottky barriers (SBs) at metal contacts. Here, we demonstrate that PdSe2/WSe2 nanosheet-based van der Waals heterostructures outperform PdSe2 or WSe2 nanosheets alone as channel materials for n-type field-effect transistors. Here, the WSe2 nanosheet serves as a buffer layer, mitigating Fermi-level pinning and reducing SBs between Ti metal and PdSe2 nanosheets. These heterostructures achieve two-terminal effective mobility exceeding 200 cm2 V–1 s–1 at room temperature and nearing 680 cm2 V–1 s–1 at 77 K. Additionally, the increased bandgap in thinner PdSe2 nanosheets enables high on/off ratios (∼107) in PdSe2/WSe2. These results underscore the potential of PdSe2/WSe2 nanosheet-based heterostructures and the importance of interfacial engineering in advancing 2D electronic devices.