Bias Stress Stability of Carbon Nanotube Transistors with Implications for Sensors

For years, carbon nanotube (CNT) field- effect transistors (CNTFETs) have been promoted for their superb performance in sensing applications [1]. As hollow cylinders of sp2-bonded carbon, CNTs have their entire crystal structure exposed and thus are highly sensitive to local charge perturbations. CNTFET -based sensors typically require constant biasing in the on-state for the duration of their operation, inducing both gate and drain bias stress in the device. Reliable sensors will require detailed understanding of the effects of this bias stress on the device performance; yet, reports of these effects to date have had limited focus, primarily studying gate bias stress [2]-[4], molecular adsorption [5], or exclusively CNT thin-film devices [2-3,7]. Additionally, these reports are limited to time scales of less than a few hours.