Complementary Doping Strategy for Achieving Low Contact-Resistance in p-Type Two-Dimensional Field-Effect Transistors.

Das, Mayukh; Mukhopadhyay, Krishnendu; Alam, Md Sajjad; Cintron-Figueroa, Daniel; Sofer, Zdenek; Terrones, Mauricio; Robinson, Joshua A; Das, Saptarshi · Nano Lett · 2026

basic_science · Level V

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Abstract

Lowering contact resistance (<i>R</i><sub>C</sub>) is essential for achieving high-performance complementary logic circuits based on two-dimensional (2D) field-effect transistors (FETs). Although n-type 2D FETs have reached sub-100 Ω·μm <i>R</i><sub>C</sub>, attaining a similar performance in p-type devices remains difficult due to large Schottky barriers for hole injection. We present a strategy to reduce <i>R</i><sub>C</sub> in p-type monolayer WSe<sub>2</sub> FETs to the sub-kΩ·μm range by combining complementary doping with a clean 2D/2D van der Waals (vdW) interface. Degenerately Ta-doped multilayer MoSe<sub>2</sub> acts as a robust p-type contact and is laminated onto the MOCVD-grown WSe<sub>2</sub> channels. A postfabrication NO anneal induces selective channel doping through NO chemisorption at Se-vacancy sites while preserving the Ta-doped MoSe<sub>2</sub> contact properties. This combined channel and contact engineering enable efficient hole injection, yielding <i>I</i><sub>ON</sub> values up to 53 μA/μm. The approach narrows the performance gap between n- and p-type 2D transistors and advances the prospects for complementary 2D logic technologies.