Sb2Te3/MoS2 Van der Waals Junctions with High Thermal Stability and Low Contact Resistance

Abstract

Two-dimensional transition metal dichalcogenides (TMDCs) demonstrate great potential in nanoelectronics devices owing to their high carrier mobility in the atomically thin channel regime. However, high contact resistance between source/drain electrodes and TMDC channels hinders the TMDCs applications in the very-large-scale integration (VLSI) field. Here, this work reports atomically aligned van der Waals (vdW) junction fabrications through thermal-induced crystallization of layered Sb2Te3 electrodes on monolayer MoS2 using VLSI-compatible physical vapor deposition and annealing processes. Due to Fermi-level unpinning with a small band offset between Sb2Te3 and MoS2 and small density of state of Sb2Te3, better device performance is demonstrated on MoS2 MOSFETs with Sb2Te3/W contact than that of Sb/W contact. Moreover, the ideal vdW junctions are found to demonstrate extreme high-thermal robustness. No intermixing at the Sb2Te3/MoS2 interface or crystallinity degradation of Sb2Te3 is observed after 450 °C annealing, leading to higher thermal stability than its Sb counterpart. Sb2Te3 is a promising candidate as an n-type contact material for TMDC-based devices such as MoS2, MoSe2, and WS2 in future VLSI electronics and various other applications.