Scalable fabrication of SnO2 thin films sensitized with CuO islands for enhanced H2S gas sensing performance

• Published in: Applied surface science 2015-01, Vol.324, p.280-285
• Main Authors: Van Toan, Nguyen, Chien, Nguyen Viet, Van Duy, Nguyen, Vuong, Dang Duc, Lam, Nguyen Huu, Hoa, Nguyen Duc, Van Hieu, Nguyen, Chien, Nguyen Duc
• Format: Article
• Language: English
• Subjects: COPPER OXIDE; CuO; FABRICATION; H2S gas sensor; Islands; Operating temperature; OXIDES; Reactive sputtering; Sensors; SnO2; THIN FILMS; Tin dioxide; TIN OXIDE; Tin oxides; Toxic; Toxicology; Wafer-scale fabrication
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.10.134

•CuO island-sensitized SnO2 thin film sensors were fabricated at wafer-scale.•SnO2–CuO island sensors significantly enhanced H2S gas response.•The thickness of CuO islands strongly affected on H2S gas sensing performance. The detection of H2S, an important gaseous molecule that has been recently marked as a highly toxic environmental pollutant, has attracted increasing attention. We fabricate a wafer-scale SnO2 thin film sensitized with CuO islands using microelectronic technology for the improved detection of the highly toxic H2S gas. The SnO2–CuO island sensor exhibits significantly enhanced H2S gas response and reduced operating temperature. The thickness of CuO islands strongly influences H2S sensing characteristics, and the highest H2S gas response is observed with 20nm-thick CuO islands. The response value (Ra/Rg) of the SnO2–CuO island sensor to 5ppm H2S is as high as 128 at 200°C and increases nearly 55-fold compared with that of the bare SnO2 thin film sensor. Meanwhile, the response of the SnO2–CuO island sensor to H2 (250ppm), NH3 (250ppm), CO (250ppm), and LPG (1000ppm) are low (1.3–2.5). The enhanced gas response and selectivity of the SnO2–CuO island sensor to H2S gas is explained by the sensitizing effect of CuO islands and the extension of electron depletion regions because of the formation of p–n junctions.