Physical Characterization and Effect of Effective Surface Area on the Sensing Properties of Tin Dioxide Thin Solid Films in a Propane Atmosphere

Sensors

Heberto Gómez-Pozos²  José Luis González-Vidal²  Gonzalo Alberto Torres²  Mar໚ de la Luz Olvera¹ 

[1] Departamento de Ingeniería Eléctrica-SEES, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, CINVESTAV-IPN, Apartado postal 14740, México D.F. 07000, Mexico; E-Mail:;Área Académica de Computación, ICBI, Universidad Autónoma del Estado de Hidalgo, Mineral de la Reforma, 56092 Hidalgo, Mexico; E-Mails:

关键词: gas sensors;    SnO₂;    thin solid films;   

DOI  :  10.3390/s140100403

来源: mdpi

【 摘 要 】

The physical properties and the effect of effective surface area (ESA) on the sensing properties of tin dioxide [SnO₂] thin films in air and propane [C₃H₈] atmosphere as a function of operating temperature and gas concentration have been studied in this paper. SnO₂ thin films with different estimated thicknesses (50, 100 and 200 nm) were deposited on glass substrates by the chemical spray technique. Besides, they were prepared at two different deposition temperatures (400 and 475 °C). Tin chloride [SnCl₄ · 5H₂O] with 0.2 M concentration value and ethanol [C₂H₆O] were used as tin precursor and solvent, respectively. The morphological, and structural properties of the as-prepared films were analyzed by AFM and XRD, respectively. Gas sensing characteristics of SnO₂ thin solid films were measured at operating temperatures of 22, 100, 200, and 300 °C, and at propane concentration levels (0, 5, 50, 100, 200, 300, 400, and 500 ppm). ESA values were calculated for each sample. It was found that the ESA increased with the increasing thickness of the films. The results demonstrated the importance of the achieving of a large effective surface area for improving gas sensing performance. SnO₂ thin films deposited by spray chemical were chosen to study the ESA effect on gas sensing properties because their very rough surfaces were appropriate for this application.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.