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Highly Sensitive H2S Sensor Based on the Metal-Catalyzed SnO2 Nanocolumns Fabricated by Glancing Angle Deposition.

Yoo KS, Han SD, Moon HG, Yoon SJ, Kang CY - Sensors (Basel) (2015)

Bottom Line: After annealing at 500 °C for 40 h, the sensors showed a polycrystalline phase with a porous, tilted columnar nanostructure.The gas sensitivities (S = Rgas/Rair) of Au and Ag-catalyzed SnO2 sensors fabricated by the GAD process were 0.009 and 0.015, respectively, under 5 ppm H2S at 300 °C, and the 90% response time was approximately 5 s.These sensors showed excellent sensitivities compared with the SnO2 thin film sensors that were deposited normally (glancing angle = 0°, S = 0.48).

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, University of Seoul, 163, Seoulsiripdae-ro, Dongdaemun-gu, Seoul 130-743, Korea. ksyoo@uos.ac.kr.

ABSTRACT
As highly sensitive H2S gas sensors, Au- and Ag-catalyzed SnO2 thin films with morphology-controlled nanostructures were fabricated by using e-beam evaporation in combination with the glancing angle deposition (GAD) technique. After annealing at 500 °C for 40 h, the sensors showed a polycrystalline phase with a porous, tilted columnar nanostructure. The gas sensitivities (S = Rgas/Rair) of Au and Ag-catalyzed SnO2 sensors fabricated by the GAD process were 0.009 and 0.015, respectively, under 5 ppm H2S at 300 °C, and the 90% response time was approximately 5 s. These sensors showed excellent sensitivities compared with the SnO2 thin film sensors that were deposited normally (glancing angle = 0°, S = 0.48).

No MeSH data available.


FESEM images. (a) Surface of SnO2 thin film (glancing angle = 0°); (b) Surface and cross-section of SnO2 thin film (glancing angle = 85°); (c) Surface and cross-section of Au-catalyzed SnO2 thin film (glancing angle = 85°); (d) Surface and cross-section of Ag-catalyzed SnO2 thin film (glancing angle = 85°).
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sensors-15-15468-f003: FESEM images. (a) Surface of SnO2 thin film (glancing angle = 0°); (b) Surface and cross-section of SnO2 thin film (glancing angle = 85°); (c) Surface and cross-section of Au-catalyzed SnO2 thin film (glancing angle = 85°); (d) Surface and cross-section of Ag-catalyzed SnO2 thin film (glancing angle = 85°).

Mentions: Surface and cross-sectional FESEM images of the SnO2 films are shown in Figure 3. Figure 3a shows an image of the SnO2 thin film (the film deposited at a glancing angle of 0°). The SnO2 thin film was relatively dense and was composed of a range of nanometer-sized grains. Alternatively, Figure 3b shows images of the SnO2 film deposited at a glancing angle of 85°, whereby its surface microstructure was nanoporous and a cross-sectional view revealed a tilted columnar structure. These results indicate that the nanocolumn sensors have larger sensor/gas contact areas than the thin film sensor of Figure 3a. As shown in Figure 3c,d, in the case of the Au- and Ag-catalyzed SnO2 nanocolumn sensors, the Au and Ag aggregated on the nanocolumn surface during the annealing process and a catalytic nanoisland was therefore formed.


Highly Sensitive H2S Sensor Based on the Metal-Catalyzed SnO2 Nanocolumns Fabricated by Glancing Angle Deposition.

Yoo KS, Han SD, Moon HG, Yoon SJ, Kang CY - Sensors (Basel) (2015)

FESEM images. (a) Surface of SnO2 thin film (glancing angle = 0°); (b) Surface and cross-section of SnO2 thin film (glancing angle = 85°); (c) Surface and cross-section of Au-catalyzed SnO2 thin film (glancing angle = 85°); (d) Surface and cross-section of Ag-catalyzed SnO2 thin film (glancing angle = 85°).
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Related In: Results  -  Collection

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sensors-15-15468-f003: FESEM images. (a) Surface of SnO2 thin film (glancing angle = 0°); (b) Surface and cross-section of SnO2 thin film (glancing angle = 85°); (c) Surface and cross-section of Au-catalyzed SnO2 thin film (glancing angle = 85°); (d) Surface and cross-section of Ag-catalyzed SnO2 thin film (glancing angle = 85°).
Mentions: Surface and cross-sectional FESEM images of the SnO2 films are shown in Figure 3. Figure 3a shows an image of the SnO2 thin film (the film deposited at a glancing angle of 0°). The SnO2 thin film was relatively dense and was composed of a range of nanometer-sized grains. Alternatively, Figure 3b shows images of the SnO2 film deposited at a glancing angle of 85°, whereby its surface microstructure was nanoporous and a cross-sectional view revealed a tilted columnar structure. These results indicate that the nanocolumn sensors have larger sensor/gas contact areas than the thin film sensor of Figure 3a. As shown in Figure 3c,d, in the case of the Au- and Ag-catalyzed SnO2 nanocolumn sensors, the Au and Ag aggregated on the nanocolumn surface during the annealing process and a catalytic nanoisland was therefore formed.

Bottom Line: After annealing at 500 °C for 40 h, the sensors showed a polycrystalline phase with a porous, tilted columnar nanostructure.The gas sensitivities (S = Rgas/Rair) of Au and Ag-catalyzed SnO2 sensors fabricated by the GAD process were 0.009 and 0.015, respectively, under 5 ppm H2S at 300 °C, and the 90% response time was approximately 5 s.These sensors showed excellent sensitivities compared with the SnO2 thin film sensors that were deposited normally (glancing angle = 0°, S = 0.48).

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, University of Seoul, 163, Seoulsiripdae-ro, Dongdaemun-gu, Seoul 130-743, Korea. ksyoo@uos.ac.kr.

ABSTRACT
As highly sensitive H2S gas sensors, Au- and Ag-catalyzed SnO2 thin films with morphology-controlled nanostructures were fabricated by using e-beam evaporation in combination with the glancing angle deposition (GAD) technique. After annealing at 500 °C for 40 h, the sensors showed a polycrystalline phase with a porous, tilted columnar nanostructure. The gas sensitivities (S = Rgas/Rair) of Au and Ag-catalyzed SnO2 sensors fabricated by the GAD process were 0.009 and 0.015, respectively, under 5 ppm H2S at 300 °C, and the 90% response time was approximately 5 s. These sensors showed excellent sensitivities compared with the SnO2 thin film sensors that were deposited normally (glancing angle = 0°, S = 0.48).

No MeSH data available.