Synthesis and photoluminescence properties of hydrothermally-grown ZnO nanowires on the aerosol-deposited AZO seed layer

A nano-grained Al-doped ZnO (AZO) seed layer with three different Al contents was deposited on soda-lime glass substrates using an aerosol deposition (AD) method at room temperature. The AZO seed layer was polycrystalline with a dense structure and random orientation. The zinc oxide (ZnO) nanowires were hydrothermally synthesized at temperatures below 100 °C on the AZO AD seed layer. The hydrothermally-grown ZnO nanowires had a diameter less than ~200 nm and a wurtzite hexagonal structure with a preferred orientation along the c direction. The photoluminescence (PL) properties of the AZO AD seed layer films revealed only one peak in the ultra-violet (UV) range. The intensity at the near band edge (NBE) emission increased with decreasing Al content in the AZO AD seed layer. On the other hand, the hydrothermally-grown ZnO showed two peaks in the PL emission spectra located in the UV and visible range. The crystallinity and PL emission properties of the ZnO nanowires were enhanced by the hydrothermal process and the doping concentration in the seed layer without the need for an annealing process.