EFFECT OF LOW-ENERGY OXYGEN PLASMA TREATMENT ON PHOTOLUMINESCENCE OF CARBON-BEARING POROUS ALUMINA

Abstract

In this study the effect of low-energy oxygen plasma treatment on the photoluminescence properties of the carbon-bearing porous alumina obtained in 0.4 M aqueous solution of tartaric acid at constant current density of 150 and 700 A m–2 was investi-gated. It was also established that in as-anodized samples carbon content is increased from 2.98 to 3.18 (wt.) % with increasing anodizing current density. Increase in current density from 150 to 700 A m–2 results only in decrease in photoluminescence intensity. Oxygen plasma treatment is shown not to change the character of the photoluminescence of the different samples, but results in the decrease in the intensity of photoluminescence in 1.2 and 2.2 times for porous alumina formed at 150 and 700 A m–2, respectively. The impact of the oxygen plasma treatment was also observed on the photoluminescence transients. It was found that in the case of the samples formed at 150 A m–2 the average life-time of the centers was decreased from 1.78 to 1.76 ns and from 1.78 to 1.50 ns for ones formed at 700 A m–2. It is associated with the oxidation of amorphous carbon embedded in porous anodic alumina due to chemical reaction with O2 plasma.