Highly sensitive MWCNTs/SiNWs hybrid nanostructured sensor fabricated on silicon-chip for alcohol vapors detection

TLDR: In this paper, vertically aligned Silicon Nanowires (SiNWs) were synthesized on Silicon (Si) chip using Metal Assisted Chemical Etching (MACE) process, which were decorated by Multiwall Carbon Nanotubes (MWCNTs) and resulted into a MWCNTs and SiNWs hybrid nanostructure.

Abstract: The present work focuses on the fabrication of highly sensitive, stable and fast response alcohol sensor using MWCNTs/SiNWs hybrid nanostructure. Herein, vertically aligned Silicon Nanowires (SiNWs) were synthesized on Silicon (Si) chip using Metal Assisted Chemical Etching (MACE) process, which were decorated by Multiwall Carbon Nanotubes (MWCNTs) and resulted into a MWCNTs/SiNWs hybrid nanostructure. These types of MWCNTs were separately grown by using Chemical Vapor Deposition (CVD) technique. The structural analysis and characterization of as-grown materials along with fabricated hybrid nanostructure were done by using different techniques such as Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Raman spectrometer and X-Ray diffractometer. The prepared materials were observed to be dense having high yield and uniformity throughout the structure. The alcohol vapors sensing properties, such as sensitivity, selectivity, repeatability, response & recovery characteristics, of the fabricated MWCNTs/SiNWs sensor, were investigated at room temperature. The data was recorded in the form of changes in sensor response with respect to time and analyzed using the mechanism of interaction of materials with the analyte gas species. The as-fabricated sensor exhibits not only excellent response ~1.42 and selectivity for alcohol concentration of 1 ppm under atmospheric conditions at room temperature but also, it's response time (3 s) and recovery time (5 s) is quite fast along with excellent reproducible nature. Most importantly, the sensor recovered to its original state without applying any external energy source. Hence, all the measured properties indicate the better operational performance of the fabricated sensor and therefore, could be suitably employed in various applications such as alcohol industries, fuel processing and other societal problems.