Metallic tellurium for p-type contacts of two-dimensional MoTe2 field-effect transistors

Abstract

While significant progress has been made in the fabrication of n-type contacts for two-dimensional field-effect transistors (2D FETs), the development of high-performance p-type counterparts using compatible techniques remains insufficient to realize competitive complementary circuits. Here, we demonstrate the growth of metallic-phase tellurium (m-Te) on MoTe2 via evaporation as an efficient p-type contact. The atomic arrangement at the Te/MoTe2 interface stabilizes m-Te under ambient conditions, forming an atomically sharp van der Waals gap with optimal band alignment and suppressed metal-induced gap states. Combined with hole doping and tellurium vacancies compensation, the interface enables barrier-free hole injection. Bilayer MoTe2 FETs employing m-Te contacts achieve a contact resistance as low as 1.6 kΩ μm, an on-state current up to 124 μA μm-1, and a maximum on/off ratio of 107, which are among the best values obtained for p-type 2D FETs. Our work unveils metallic-phase chalcogen as a promising approach for contact optimization.