Synthesis and characterization of carbon nanotube doped with zinc oxide nanoparticles CNTs-ZnO/PS as ethanol gas sensor

Abstract

Nanocomposites have the potential to produce very selective, stable, and sensitive sensors. Nanocomposites porous structures have a larger surface area for gas molecule adsorption. In this paper, the high quality gas sensor was prepared by modified porous layer of silicon (PS) with a thin layer of carbon nanotube (CNTs) and carbon nanotube doped with zinc oxide (ZnO) nanoparticles (70–30)% respectively. PS samples were created using the photoelectrochemical etching method (PECE), for N-type silicon (Si) wafer with resistivity of (1.5–4) Ω cm and a thickness (580 ± 0.25) μm. Three etching current densities were employed for prepare PS layers 12, 24, and 30 mA/cm2, while, the hydrofluoric acid HFc concentration of 40% and etching time was about 10 min. The Structure characteristics, morphological features, and surface chemical bond formation of all PS and (MWCNTs-ZnO/PS) samples were examined using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and Transition Electron Microscope (TEM). All PS and MWCNTs-ZnO/PS samples were applied as ethanol gas sensors at room temperature. The results revealed that CNTs-ZnO/PS had the highest sensitivity to ethanol gas at etching current density 30 mA/cm2, reaching about (2.004984) at a concentration of 500 ppm. Fusion of CNTs-ZnO leads to the emergence of new properties and unique effects, and as a result of the excellent sensing ability of carbon nanotubes in detecting different gases at room temperature, Used in the manufacture of highly selective gas sensors that operate at room temperature. The Interest of this article return to study the effect of extremely high surface to volume ratio (increasing surface area), and ease composition and compatibility with modern silicon microelectronics manufacturing technologies.