Achieving Ultrahigh Electron Mobility in PdSe2 Field-Effect Transistors via Semimetal Antimony as Contacts

Even though atomically thin 2D semiconductors have shown great potential for next-generation electronics, the low carrier mobility caused by poor metal-semiconductor contacts and the inherently high density of impurity scatterings remains a critical issue. Herein, high-mobility field-effect transistors (FETs) by introducing few-layer PdSe2 flakes as channels is achieved, via directly depositing semimetal antimony (Sb) as drain-source electrodes. The formation of clean and defect-free van der Waals (vdW) stackings at the Sb-PdSe2 heterointerfaces boosts the room temperature transport characteristics, including low contact resistance down to 0.55 kO mu m, high on-current density reaching 96 mu A mu m(-1), and high electron mobility of 383 cm(2) V-1 s(-1). Furthermore, metal-insulator transition (MIT) is observed in the PdSe2 FETs with and without hexagonal boron nitride (h-BN) as buffer layers. However, the layered h-BN/PdSe2 vdW stacking eliminates the interference of interfacial disorders, and thus the corresponding device exhibits a lower MIT crossing point, larger mobility exponent of gamma similar to 1.73, significantly decreased hopping parameter of T-0, and ultrahigh electron mobility of 2,184 cm(2) V-1 s(-1) at 10 K. These findings are expected to be significant for developing high mobility 2D-based quantum devices.

Automated summary

High-mobility field-effect transistors (FETs) are achieved by introducing few-layer PdSe2 flakes as channels and directly depositing semimetal antimony (Sb) as drain-source electrodes. The formation of clean and defect-free van der Waals (vdW) stackings at the Sb-PdSe2 heterointerfaces boosts the transport characteristics, while the use of layered h-BN as buffer layers eliminates interfacial disorders and significantly increases electron mobility.