TY  - JOUR
AU  - Dube, I.
AU  - Jiménez, D.
AU  - Fedorov, G.
AU  - Boyd, A.
AU  - Gayduchenko, I.
AU  - Paranjape, M.
AU  - Barbara, P.
PY  - 2015
DA  - 2015//
TI  - Understanding the electrical response and sensing mechanism of carbon-nanotube-based gas sensors
T2  - Carbon
JO  - Carbon
SP  - 330
EP  - 337
VL  - 87
KW  - carbon nanotubes
KW  - CNT detectors
KW  - field effect transistors
KW  - FET
AB  - Gas sensors based on carbon nanotube field effect transistors (CNFETs) have outstanding sensitivity compared to existing technologies. However, the lack of understanding of the sensing mechanism has greatly hindered progress on calibration standards and customization of these nano-sensors. Calibration requires identifying fundamental transistor parameters and establishing how they vary in the presence of a gas. This work focuses on modeling the electrical response of CNTFETs in the presence of oxidizing (NO2) and reducing (NH3) gases and determining how the transistor characteristics are affected by gas-induced changes of contact properties, such as the Schottky barrier height and width, and by the doping level of the nanotube. From the theoretical fits of the experimental transfer characteristics at different concentrations of NO2 and NH3, we find that the CNTFET response can be modeled by introducing changes in the Schottky barrier height. These changes are directly related to the changes in the metal work function of the electrodes that we determine experimentally, independently, with a Kelvin probe. Our analysis yields a direct correlation between the ON – current and the changes in the electrode metal work function. Doping due to molecules adsorbed at the carbon-nanotube/metal interface also affects the transfer characteristics.
SN  - 0008-6223
UR  - https://linkinghub.elsevier.com/retrieve/pii/S0008622315000858
UR  - https://doi.org/10.1016/j.carbon.2015.01.060
DO  - 10.1016/j.carbon.2015.01.060
N1  - exported from refbase (https://db.rplab.ru/refbase/show.php?record=1778), last updated on Tue, 01 Jun 2021 13:08:38 -0500
ID  - Dube_etal2015
ER  -