Gate bias stress effect in single-walled carbon nanotubes field-effect-transistors

This paper deals with the effect of negative gate bias stress with different times on the Carbon Nanotube Field Effect Transistor (CNTFET) based gas sensors, obtained using Single-Walled Carbon Nanotubes (SWCNTs) mats as channel. The effects of Gate Bias Stress (GBS) on transistor performance are important; hence it is necessary to understand how our device behaves under bias stress. To perform this work, I-V characteristics, are taken by applying a constant gate voltage (V-gs) for an extended time. I-V characteristics after stress exhibited an identical shape to the one before stress with an important degradation of the current that flows through the transistors. A possible source of the Bias Stress Effect (BSE) is traps in the semiconductor itself which are spatially and energetically isolated due to the disorder of SWCNTs. This hypothesis will be confirmed by the saturation of the drain current shift Delta I after a prolonged period of time. All isolated trap states are saturated and only electrical traps still active and give us the original I-V characteristics.