Precise growth and integration of carbon nanotubes through optical control

Extensive and practical applications of carbon nanotubes (CNTs) in the field of electronics and devices require precisely controlled growth and integration of CNTs into predesigned micro/nanoarchitectures. Several critical topics, including where it starts, where it goes, alignment direction, and electrical types, have to be addressed to meet the challenges. Tremendous investigations have been made on the topics. However, due to existing drawbacks of individual approaches, such as high substrate temperature, coarse integration, mixed electrical types, liquid phase processing, reliability, yield and cost, high-performance-on-demand solutions are still vacant. In this study, we investigated several laser-based strategies to address the challenges. Parallel integration of CNTs into pre-designed micro/nano-architectures was achieved in a single-step laser-assisted chemical vapor deposition (LCVD) process at a relative low substrate temperature by making use of optical near-field effect. Growing CNT arrays of controlled alignments was achieved by applying external electrical biases of different polarities to influence the movement of catalyst particles in the LCVD process. CNT-based field-effect transistors (CNT-FETs) containing only semiconducting CNTs were obtained in a scalable manner through an optically controlled approach. The laser-based strategies investigated in this study suggest a laser-based solution-package to meet the challenges for practical applications of CNTs, and promises a reliable and scalable approach to achieve CNT-integrated devices.