Low-voltage complementary inverters based on ion gel-gated ReS₂ and BP transistors

We demonstrated the preparation of low-voltage complementary inverters based on transistors made of ion gel-gated 2D materials. Mechanically-exfoliated ReS₂ was utilized as an n-type semiconductor. The ultrahigh capacitance (6 μF/cm²) and long-range polarizability of the ion gel gate dielectric layer provided low-voltage operation below 2 V and allowed a coplanar-gate configuration of the transistors. The ion gel-gated ReS₂ transistors exhibited excellent device performance including an electron mobility of 6.7 cm²/Vs and an on-off current ratio of ∼10⁴. Both the charge-transport mechanism and the contact properties of the device were investigated systematically by measuring the temperature-dependent electrical properties. Mechanically-exfoliated black phosphorous (BP) or WSe₂ was employed as the p-type counterpart semiconductors to fabricate the complementary inverter. The resulting 2D complementary inverter exhibited low-voltage operation below 2 V with clear signal inversion. The proposed low-voltage ion gel-gated complementary inverter based on 2D materials opens up new opportunities for realizing future electronics based on 2D materials.