Photoluminescence of Cr3+ in nanostructured Al2O3 synthesized by evaporation using a continuous wave CO2 laser

Laser evaporation of an Al2O3 target by a continuous wave CO2 laser was used to obtain nanostructured Al2O3 condensates with a mean crystallite size of 6 nm, one nominally pure and another doped with chromium at a concentration of 0.2 wt%. Photoluminescence of Cr3+ was observed in all the samples of the Al2O3 condensate. In all the Al2O3 condensates the α-Al2O3 phase, undetectable by XRD and HRTEM, was revealed by Cr3+ probing. Photoluminescence studies with the use of Cr3+ as a probe also revealed the θ- and (γ + δ)-crystal phases of Al2O3; this finding was supported by XRD and HRTEM data.