The Continuous demand from the industry, for small and low-power consumer electronics, motivates us to seek new ways for design enhancements. With numerous technologies available and upcoming for the fabrication of semiconducting devices, the selection of technology that can be termed as the future of industry requires weighing them against various requirements, constraints, and parameters. Here some new low-power, high-speed full adder circuits using carbon nanotube field-effect transistor for real-time, fault-tolerant, and mission-critical applications is presented.