Functionalized Carbon Nanotubes on Porous Silicon for Sensing Application

Authors Sally K. Abbas, Asama N. Naje

Baghdad University, College of Science, Physics Department, Baghdad, Iraq

Issue Volume 11, Year 2019, Number 5
Dates Received 23 June 2019; revised manuscript received 08 October 2019; published online 25 October 2019
Citation Sally K. Abbas, Asama N. Naje, J. Nano- Electron. Phys. 11 No 5, 05015 (2019)
PACS Number(s) 61.48.De
Keywords F-SWCNTs, F-MWCNTs, Oxidizing gas, Sensitivity (11) , Response time (3) , Porous silicon (3) .

The evolution of carbon nanotube (CNTs) based gas sensors has attracted great interest among researchers in the last decade because of their selectivity for various gaseous media, fast response, high sensitivity and room temperature operation. Functionalized single-walled carbon nanotubes (F-SWCNTs) and functionalized multi-walled carbon nanotubes (F-MWCNTs) have been utilized to manufacture nitrogen dioxide gas sensor. CNTs films have been deposited on (n-type) porous silicon substrate by the drop casting technique. A porous silicon layer (PS) was prepared using the photo-electrochemical etching. The applied current density is 20 mA/cm2 with green laser radiation, and the typical photo-electrochemical etching time was about 15 min. When the F-SWCNTs and F-MWCNTs samples were exposed to NO2 gas at different operating temperatures, the sensitivity response results show that the F-SWCNTs have better performance than the F-MWCNTs. At 200 °C the F-SWCNTs/PS sensitivity reaches 61%, the response time and the recovery time were about 10 s and 214 s, respectively; whereas for the F-MWCNTs/PS the sensitivity reaches 57 % at 100 °C, the response time and the recovery time were about 20 s and 647 s, respectively. At the same time, the F-MWCNTs have an operating temperature (100 °C) less than that of the F-SWCNTs (200 °C).

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