Polarity Control and Weak Fermi-Level Pinning in PdSe2 Transistors

Two-dimensional (2D) materials have been considered key materials for the future logic devices due to the excellent electrostatic integrity originating from their ultrathin nature. However, the carrier polarity control of 2D material field-effect transistors (FETs) still remains a challenging issue, hindering the realization of complementary logic function in the 2D material platform. Here, we report a comprehensive study on the electrical characteristics of PdSe2 FETs with different metal contacts. It is found that the carrier polarity in PdSe2 FETs can be modulated simply by changing the metal contact due to the weak Fermi-level pinning in PdSe2. We demonstrate a complementary metal-oxide-semiconductor (CMOS) inverter using the same channel material PdSe2 for n- and p-MOSFETs but with different metal contacts, suggesting the possible realization of PdSe2-based CMOS logic circuits.