Investigation on Sensing Performance of Highly Doped Sb/SnO[sub.2]

• Published in: Sensors (Basel, Switzerland) Switzerland), 2022-02, Vol.22 (3)
• Main Authors: Feng, Zhifu, Gaiardo, Andrea, Valt, Matteo, Fabbri, Barbara, Casotti, Davide, Krik, Soufiane, Vanzetti, Lia, Ciana, Michele Della, Fioravanti, Simona, Caramori, Stefano, Rota, Alberto, Guidi, Vincenzo
• Format: Article
• Language: English
• Subjects: Sensors
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22031233

Tin dioxide (SnO[sub.2]) is the most-used semiconductor for gas sensing applications. However, lack of selectivity and humidity influence limit its potential usage. Antimony (Sb) doped SnO[sub.2] showed unique electrical and chemical properties, since the introduction of Sb ions leads to the creation of a new shallow band level and of oxygen vacancies acting as donors in SnO[sub.2]. Although low-doped SnO[sub.2]:Sb demonstrated an improvement of the sensing performance compared to pure SnO[sub.2], there is a lack of investigation on this material. To fill this gap, we focused this work on the study of gas sensing properties of highly doped SnO[sub.2]:Sb. Morphology, crystal structure and elemental composition were characterized, highlighting that Sb doping hinders SnO[sub.2] grain growth and decreases crystallinity slightly, while lattice parameters expand after the introduction of Sb ions into the SnO[sub.2] crystal. XRF and EDS confirmed the high purity of the SnO[sub.2]:Sb powders, and XPS highlighted a higher Sb concentration compared to XRF and EDS results, due to a partial Sb segregation on superficial layers of Sb/SnO[sub.2]. Then, the samples were exposed to different gases, highlighting a high selectivity to NO[sub.2] with a good sensitivity and a limited influence of humidity. Lastly, an interpretation of the sensing mechanism vs. NO[sub.2] was proposed.