A Universal van der Waals Tunneling Injector for Monolayer CMOS

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Abstract
Two‐dimensional (2D) semiconductors are poised to extend logic technology to the atomic‐thickness limit, yet monolayer complementary metal‐oxide‐semiconductor (CMOS) has been largely hampered by polarity‐dependent, thermionic‐emission‐dominated contacts that preclude a unified injection solution. Here, we introduce degenerately doped, crystalline SnSe 2 as a universal source‐side van der Waals (vdW) injector capable of enforcing all‐tunneling carrier injection into both p ‐ and n ‐type monolayer channels. The combination of a large electron affinity (∼5.1 eV), degenerate carrier density (>10 19 cm −3 ), and atomically uniform vdW interfacial coupling enables polarity‐tailored tunneling mechanisms while effectively suppressing interfacial gap states. In p ‐type WSe 2 , a type‐III (broken gap) alignment drives efficient band‐to‐band tunneling, yielding a >1000‐fold enhancement in drive current over conventional metal electrodes. In n ‐type MoS 2 , the SnSe 2 injector forms a type‐I heterojunction within the sub‐depletion‐width monolayer body, enabling a gate‐tunable injection that evolves from field‐controlled Fowler–Nordheim‐like tunneling to thickness‐limited tunneling, achieving an on/off ratio > 10 9 and a subthreshold swing below 70 mV dec −1 . Integrating this single‐material injector, we demonstrate a monolayer CMOS inverter with a maximum voltage gain of ∼340 at V DD = 2 V, establishing degenerate SnSe 2 as a dual‐polarity vdW injector and providing a platform for high‐performance, low‐power 2D integrated circuits.
Funding Information
  • Ministry of Science and ICT, South Korea (RS‐2024‐00336695)
  • Ministry of Science and ICT, South Korea (RS‐2024‐00444182)
  • Ministry of Science and ICT, South Korea (RS‐2025‐23323754)
  • Ministry of Science and ICT, South Korea (RS‐2025‐23323228)
  • Ministry of Science and ICT, South Korea (RS‐2026‐25542094)
  • Ministry of Education (RS‐2025‐02633565)
  • National Natural Science Foundation of China (12393831)

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