Synthesis of Tin Nitride Sn x N y Nanowires by Chemical Vapour Deposition
1 Nanostructured Materials and Devices Laboratory, Department of Mechanical and Manufacturing Engineering, Materials Science Group, University of Cyprus, P.O. Box 20537, 1678, Nicosia, Cyprus
2 Department of Physics, Research Centre of Ultrafast Science, University of Cyprus, P.O. Box 20537, 1678, Nicosia, Cyprus
Nanoscale Research Letters 2009, 4:1103-1109 doi:10.1007/s11671-009-9364-0Published: 20 June 2009
Tin nitride (SnxNy) nanowires have been grown for the first time by chemical vapour deposition on n-type Si(111) and in particular by nitridation of Sn containing NH4Cl at 450 °C under a steady flow of NH3. The SnxNynanowires have an average diameter of 200 nm and lengths ≥5 μm and were grown on Si(111) coated with a few nm’s of Au. Nitridation of Sn alone, under a flow of NH3is not effective and leads to the deposition of Sn droplets on the Au/Si(111) surface which impedes one-dimensional growth over a wide temperature range i.e. 300–800 °C. This was overcome by the addition of ammonium chloride (NH4Cl) which undergoes sublimation at 338 °C thereby releasing NH3and HCl which act as dispersants thereby enhancing the vapour pressure of Sn and the one-dimensional growth of SnxNynanowires. In addition to the action of dispersion, Sn reacts with HCl giving SnCl2which in turn reacts with NH3leading to the formation of SnxNyNWs. A first estimate of the band-gap of the SnxNynanowires grown on Si(111) was obtained from optical reflection measurements and found to be ≈2.6 eV. Finally, intricate assemblies of nanowires were also obtained at lower growth temperatures.