An Ultra-Flexible Solution-Processed Metal-Oxide/Carbon Nanotube Complementary Circuit Amplifier with Highly Reliable Electrical and Mechanical Stability

Here, high-performance flexible complementary metal-oxide–semiconductor (CMOS) amplifiers with extremely stable electro-mechanical characteristics by employing low-temperature solution-processed amorphous indium–gallium–zinc oxide (a-IGZO) and single-walled carbon nanotube (SWCNT) thin film transistors (TFTs) is demonstrated. The photochemical-activated combustion sol–gel a-IGZO and SWCNT TFTs show average saturation mobility of 6.82 and 0.51 cm² V⁻¹ s⁻¹, respectively. Based on the devices, a-IGZO/SWCNT-based CMOS amplifiers are implemented on ultrathin and flexible substrates (thickness of ≈3 µm), exhibiting small-signal gain and unity-gain bandwidth of up to 25 dB and 25 kHz, respectively, with highly reliable characteristics from 1000 bending stress (radius of 125 µm) and positive gate bias stress conditions (for up to 3 h). The underlying mechanisms of the CMOS performance combined with large output impedance of the SWCNT load are investigated in detail via various circuit implementations and automatic integrated circuit modeling Spice simulation and comprehensive electrical analysis. To ensure the viability of the extremely stable electromechanical properties of the flexible amplifier, a numerical analysis is carried out based on finite-element methods with an integrated circuit emphasis to find the best match of the CMOS architecture and optimized structural integrity, verifying highly reliable and scalable skin-like electronics.