Mechanism Exploration of Enhanced Biosensing Performance for All-Carbon-Nanotube Thin-Film Transistors

Biosensors based on carbon nanotube (CNT) thin-film transistors (TFTs) have outstanding potential for ultrasensitive and label-free DNA detection. However, at present, the sensing mechanisms of the all-carbon-nanotube biosensors with metallic CNTs as electrodes are still controversial. In this work, a platform is established for universal DNA detection. By analyzing the biosensor responses obtained by passivating the channel, electrodes and contact of the biosensors, respectively, the sensing mechanisms can be clearly investigated. It is found that the electrostatic gating is dominant, while the Schottky barrier modulation plays a relatively minor role, where the Schottky barrier height is co-modulated by the adsorbed DNA in the channel and electrodes.