TY  - JOUR
A1  - Sousa, Marcos A. M.
A1  - Siqueira, Jose R. Jr.
A1  - Vercik, Andres
A1  - Schöning, Michael Josef
A1  - Oliveira, Osvaldo N. Jr.
T1  - Determining the optimized layer-by-layer film architecture with dendrimer/carbon nanotubes for field-effect sensors
JF  - IEEE Sensors Journal
N2  - The capacitive electrolyte–insulator–semiconductor (EIS) structure is a typical device based on a field-effect sensor platform. With a simple silicon-based structure, EIS have been useful for several sensing applications, especially with incorporation of nanostructured films to modulate the ionic transport and the flat-band potential. In this paper, we report on ion transport and changes in flat-band potential in EIS sensors made with layer-by-layer films containing poly(amidoamine) (PAMAM) dendrimer and single-walled carbon nanotubes (SWNTs) adsorbed on p-Si/SiO 2 /Ta 2 O 5 chips with an Al ohmic contact. The impedance spectra were fitted using an equivalent circuit model, from which we could determine parameters such as the double-layer capacitance. This capacitance decreased with the number of bilayers owing to space charge accumulated at the electrolyte–insulator interface, up to three PAMAM/SWNTs bilayers, after which it stabilized. The charge-transfer resistance was also minimum for three bilayers, thus indicating that this is the ideal architecture for an optimized EIS performance. The understanding of the influence of nanostructures and the fine control of operation parameters pave the way for optimizing the design and performance of new EIS sensors.
Y1  - 2017
U6  - http://dx.doi.org/10.1109/JSEN.2017.2653238
SN  - 1558-1748
VL  - 17
IS  - 6
SP  - 1735
EP  - 1740
PB  - IEEE
CY  - New York
ER  -