Structural, surface morphology and novel gas sensing properties of chemically deposited CdS-PVA nanocomposites; Impact of thiourea content

Abstract

In this work, the impact of thiourea (TU) concentration (0.1, 0.15, and 0.2) M on the structure, surface topography, and morphology of CdS-PVA nanocomposites NCs thin film was investigated. Crystal structure (XRD) results revealed that all films had a polycrystalline structure of CdS phase with the presence of PVA wide peak at 2θ 22°. The crystallite size was increased (10–14) nm with an increase in the TU concentrations. The AFM results revealed that the film's roughness and the Root Mean Square (RMS) roughness was increased as TU concentrations increased. The FESEM results showed that the surface morphology of CdS-PVA films tends to be porous structures, and the pore size increases with the increase of TU concentration. The fabricated CdS-PVA nanocomposite gas sensors were tested at operating temperatures of (100, 200, and 300) °C. The results showed a high sensitivity for NO2 gas at an operating temperature of 200 °C for the TU concentration of 0.2 M and the sensitivity increased as the NO2 gas concentration increased. The novel results are connected with the fabrication of CdS-PVA nanocomposites as good nitrogen dioxide sensors.

Keywords

• Cadmium sulfide
• Polyvinyl alcohol
• Nanoparticles
• Thiourea
• NO2 gas
• sensors