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 PdSe 2 /WSe 2 nanosheet-based van der Waals heterostructures outperform PdSe 2 or WSe 2 nanosheets alone as channel materials for n-type field-effect transistors. Here, the WSe 2 nanosheet serves as a buffer layer, mitigating Fermi-level pinning and reducing SBs between Ti metal and PdSe 2 nanosheets. These heterostructures achieve two-terminal effective mobility exceeding 200 cm 2 V –1 s –1 at room temperature and nearing 680 cm 2 V –1 s –1 at 77 K. Additionally, the increased bandgap in thinner PdSe 2 nanosheets enables high on/off ratios (∼10 7 ) in PdSe 2 /WSe 2 . These results underscore the potential of PdSe 2 /WSe 2 nanosheet-based heterostructures and the importance of interfacial engineering in advancing 2D electronic devices.