Physical properties investigation and gas sensing mechanism of Al: Fe2O3 thin films deposited by spray pyrolysis

• Published in: Superlattices and microstructures Vol. 129; pp. 91 - 104
• Main Authors: Ben Ayed, Rihab, Ajili, Mejda, Garcia, Jorge M., Labidi, Ahmed, Turki, Najoua Kamoun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2019
• Subjects: Aluminum doping; Gas sensing; Iron oxide; Physical properties; Spray pyrolysis; Gas sensing; Iron oxide; Spray pyrolysis; Physical properties; Aluminum doping
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2019.03.002

We present the successful synthesis and characterization of pure and Al: Fe2O3 thin films prepared by spray pyrolysis. The XRD analysis showed a rhomboedric structure with (104) as a preferential orientation for all the layers. AFM and SEM observations exhibited a dense surface with grains uniformly distributed. Optical measurements demonstrated that Al: Fe2O3 (y = 6 and 8 at. %) were highly transparent. In addition, the band gaps values found in the range from 1.98 to 2.17 eV. Hall Effect measurements indicated an n-type conductivity with the lowest resistivity of 2.68 x 102 Ω.cm which reached for the 8 at. % Al: Fe2O3 thin films. Moreover, Al: Fe2O3 thin film based sensor demonstrated a good response to a small amount of ethanol vapor with the adequate response and recovery period at a low operating temperature equal to 250 °C. •The n-type Fe2O3:Al thin films with low resistivity were obtained by spray method.•All the thin films of Fe2O3:Al have (104) as a preferential orientation.•The electrical properties of Fe2O3:Al are extremely sensitive to the aluminum doping.•Film doped with 8 at. % Al concentration exhibits a fast response to low gas concentration.