On the Performance of Solution-Processable Random Network Carbon Nanotube Transistors: Unveiling the Role of Network Density and Metallic Tube Content

This paper reveals the influence of network density and metallic tube content on the performance of random network-based carbon nanotube field-effect transistors (CNTFETs) in terms of on-current, on/off ratio, and field-effect mobility. Network density and metallic tube content are two main design factors for random network-based CNTFETs besides variation of the device layout. We conducted a systematic study based on a set of more than 100 solution-processed back-gated CNTFETs with various network densities and metallic tube contents. The on-current and on/off ratio are found to be determined by the metallic tube density, a parameter defined as network density multiplying metallic tube content. The field-effect mobility has a curve shape varying with network density, while its amplitude is determined by metallic tube content of carbon nanotube (CNT) networks. Our results experimentally reveal the influence of those factors on transistor device performance, thus providing guidelines for design and optimization of random network-based CNTFETs, opening up new perspectives for printed electronics. In addition, a percolation model based on the Monte Carlo method was used for simulating the electrical characteristics of CNT devices, offering a basis for further device engineering.