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

Abstract

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.