The morphology of tin cluster assembled films and the effect of nitrogen

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Vol. 61; no. 1; pp. 81 - 85
• Main Authors: Watson, T. F., Belić, D., Convers, P. Y., Boyd, E. J., Brown, S. A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2011; EDP Sciences
• Subjects: Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Clusters; Coalescence; Coalescing; Deposition; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Molecular; Morphology; Nitrides; Optical and Plasma Physics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Information Technology; Quantum Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Silicon nitride; Silicon substrates; Spectroscopy/Spectrometry; Spintronics; Tin; Nitride Layer; Deposition Rate; Granular Film; Cluster Size Distribution; Sensor Chip; Thin films; Grain size; Cluster size; Tin nitride; Hydrogen; Tin oxide; Tin; Silicon; Nitrogen; Gas detector
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/e2010-00264-7

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Thin films produced by depositing tin clusters with sizes between 5 and 10 nm onto silicon nitride substrates were found to be highly coalesced resulting in grains with sizes ~30 nm. Exposing the clusters to nitrogen before they were deposited significantly reduced the coalescence between them and resulted in granular films where the clusters mostly retained their shape. This is due to a small amount of tin nitride forming in the clusters. The coalesced and granular films were used to fabricate tin oxide gas sensors. This was done by depositing the two types of films onto silicon nitride chips and then oxidising them by baking at 250 °C for 24 h. It was found that the sensors composed of uncoalesced clusters were much more sensitive to hydrogen. This was attributed to the smaller grain size and the larger surface area of the granular films.