Enhancement of Room Temperature Ethanol Sensing by Optimizing the Density of Vertically Aligned Carbon Nanofibers Decorated with Gold Nanoparticles

Mostafa Shooshtari; Leandro Nicolas Sacco; Joost Van Ginkel; Sten Vollebregt; Alireza Salehi

doi:10.3390/ma15041383

Enhancement of Room Temperature Ethanol Sensing by Optimizing the Density of Vertically Aligned Carbon Nanofibers Decorated with Gold Nanoparticles

Materials (Basel). 2022 Feb 13;15(4):1383. doi: 10.3390/ma15041383.

Authors

Mostafa Shooshtari¹, Leandro Nicolas Sacco², Joost Van Ginkel², Sten Vollebregt², Alireza Salehi¹

Affiliations

¹ Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran 1631714191, Iran.
² Laboratory of Electronic Components, Department of Microelectronics, Technology and Materials (ECTM), Delft University of Technology, 2628 CD Delft, The Netherlands.

Abstract

An ethanol gas sensor based on carbon nanofibers (CNFs) with various densities and nanoparticle functionalization was investigated. The CNFs were grown by means of a Plasma-Enhanced Chemical Vapor Deposition (PECVD), and the synthesis conditions were varied to obtain different number of fibers per unit area. The devices with a larger density of CNFs lead to higher responses, with a maximal responsivity of 10%. Furthermore, to simultaneously improve the sensitivity and selectivity, CNFs were decorated with gold nanoparticles by an impaction printing method. After metal decoration, the devices showed a response 300% higher than pristine devices toward 5 ppm of ethanol gas. The morphology and structure of the different samples deposited on a silicon substrate were characterized by TEM, EDX, SEM, and Raman spectroscopy, and the results confirmed the presence of CNF decorated with gold. The influence of operating temperature (OT) and humidity were studied on the sensing devices. In the case of decorated samples with a high density of nanofibers, a less-strong cross-sensitivity was observed toward a variation in humidity and temperature.

Keywords: Plasma-Enhanced Chemical Vapor Deposition (PECVD); aerosol printing; carbon nanofiber (CNF); decorated CNF; fiber per unit area; gas sensor.