Surface passivation and conversion of SnO2 to SnS2 nanowires

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 198; pp. 10 - 13
• Main Authors: Zervos, M., Mihailescu, C.N., Giapintzakis, J., Othonos, A., Luculescu, C.R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2015
• Subjects: Density; Electron gas; Materials science; Nanowires; Photoluminescence; Rutile; Sulphur passivation; Tin dioxide; Tin disulphide; Tin oxide; Tin oxides; Tin disulphide; Nanowires; Tin oxide; Sulphur passivation
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2015.03.006

•SnO2 nanowires contain SnS2 after exposure to H2S up to 300°C.•The resistance of SnO2 nanowires is reduced significantly after exposure to H2S at 300°C.•SnO2 nanowires are fully converted to SnS2 at 400°C under H2S.•The photoluminescence of SnO2/SnS2 nanowires does not change upon exposure to H2S.•SnO2 nanowires are converted into SnS2 crystals upon exposure to H2S above 400°C. SnO2 nanowires have been grown on Si(001) via the vapour–liquid–solid mechanism at 800°C and then exposed to H2S between 300 and 600°C. The SnS2/SnO2 nanowires obtained at 300°C consist of tetragonal rutile SnO2 and hexagonal SnS2, exhibited defect related photoluminescence at 2.4eV and have smaller resistances than the SnO2 nanowires. We show how the Fermi level pinning at the surface of a SnS2/SnO2 nanowire would lead to an increase of the one dimensional electron gas density, smaller barrier height and resistance. The SnO2 nanowires are fully converted into hexagonal SnS2 at 400°C resulting into photoluminescence at 2.4 and 2.8eV but have considerably larger resistances than the SnO2 nanowires which are eliminated and converted into SnS2 crystals above 400°C.