Triply degenerate semimetal PtBi₂ as van der Waals contact interlayer in two-dimensional transistor

AbstractThe low-energy electronic excitations in topological semimetal yield a plethora of a range of novel physical properties. As a relatively scarce branch, the research of triple-degenerate semi-metal is mostly confined to the stage of physical properties and theoretical analysis, there are still challenges in its practical application. This research showcases the first application of the triply degenerate semimetal PtBi₂ in electronic devices. Leveraging a van der Waals transfer method, PtBi₂ flakes were used as interlayer contacts for metal electrodes and WS₂ in transistors. The transistor achieved a switching ratio above 10⁶ and average mobility can reach 85 cm²V⁻¹ s⁻¹, meeting integrated circuit requirements. Notably, the excellent air stability of PtBi₂ simplifies the device preparation process and provides more stable device performance. Transfer process reduces the Schottky barrier between metal electrodes and semiconductors while avoiding Fermi pinning during metal deposition to achieve excellent contact. This groundbreaking work demonstrates the practical applicability of PtBi₂ in the field of electronic devices while opening new avenues for the integration of novel materials in semiconductor technology, setting a precedent for future innovations.