High-Performance Carbon Nanotube Complementary Electronics and Integrated Sensor Systems on Ultrathin Plastic Foil.

Abstract

The longtime vacancy of high-performance complementary metal-oxide-semiconductor (CMOS) technology on plastics is a non-negligible obstacle to the applications of flexible electronics with advanced functions, such as continuous health monitoring with in situ signal processing and wireless communication capabilities, in which high speed, low power consumption, and complex functionality are desired for integrated circuits (ICs). Here, we report the implementation of carbon nanotube (CNT)-based high-performance CMOS technology and its application for signal processing in an integrated sensor system for human body monitoring on ultrathin plastic foil with a thickness of 2.5 μm. The performances of both the p- and n-type CNT field-effect transistors (FETs) are excellent and symmetric on plastic foil with a low operation voltage of 2 V: width-normalized transconductances ( gm/ W) as high as 4.69 μS/μm and 5.45 μS/μm, width-normalized on-state currents reaching 5.85 μA/μm and 6.05 μA/μm, and mobilities up to 80.26 cm2·V-1·s-1 and 97.09 cm2·V-1·s-1, respectively, together with a current on/off ratio of approximately 105. The devices were mechanically robust, withstanding a curvature radius down to 124 μm. Utilizing these transistors, various high-performance CMOS digital ICs with rail-to-rail output and a ring oscillator on plastics with an oscillation frequency of 5 MHz were demonstrated. Furthermore, an ultrathin skin-mounted humidity sensor system with in situ frequency modulation signal processing capability was realized to monitor human body sweating.