Growth behaviour of ZnO thin films and nanowires on SrTiO3 substrates

We report on comparative investigations of ZnO thin films and nanowires grown on SrTiO3 (STO) single crystal substrates. Using pulsed laser deposition technique, we could grow ZnO thin films with ( 11 2 ¯ 0 )- and (0001)-orientations on (100)- and (110)-orientated STO substrates, respectively. ZnO nanowires, grown by vapour condensation method with Au catalyst layers, did not show preferential alignment on either of the STO substrates. When the ZnO(0001)/STO(110) film was used as seed layer, we obtained dense and vertically aligned nanowires. Whereas, few and inclined nanowires were grown on the ZnO( 11 2 ¯ 0 )/STO(100) film. We discuss possible origins to cause all the observations.