a ZnO nanowires with uniform diameters grown on p-type Si (100) substrates. b–d show nanowires with a constant decrease in diameter along the axis grown at a higher flow rate and temperature. The growth time for figures (b) and (c) were 10 min and that for figures (e) and (f) were 25 min. Scales in all the figures are 2 μm.
Kar et al. Nanoscale Res Lett 2011 6:3 doi:10.1007/s11671-010-9738-3