Study on synthesis and optical properties of Al-doped ZnO hierarchical nanostructures

Highly densified Al-doped ZnO (denoted as Al-ZnO) hierarchical nanostructures were synthesized on transparent quartz substrate by chemical vapor deposition. It is found that the heating temperature plays a key role on controlling the morphologies of the Al-ZnO hierarchical nanostructures through a temperature dependent migration of Al atoms. Such uneven distribution of Al element in the hierarchical nanostructures is clearly evidenced by the x-ray photoelectron spectrum (XPS) measurements. The obtained Al-ZnO hierarchical nanostructures have transmittance of above 60% in the visible region. The photoluminescence (PL) spectra at low-temperature (20 K) were also measured.