Change in the surface morphology and chemical composition of some oxide crystals under UV laser irradiation

The effect of the 248-nm KrF and 355-nm YAG:Nd³⁺ laser radiation on the surface morphology and chemical composition of SrTiO₃, Sr₂RuO₄, PbMoO₄, LiNbO₃, Y₃Al₅O₁₂, and Al₂O₃ crystals has been studied. A relationship between the laser energy density on the sample surface and the surface roughness caused by the irradiation is determined. A technique for determining exactly the geometric surface characteristics is proposed. The effect of the surface roughness on the results of energy-dispersive X-ray (EDX) microanalysis has been investigated. A method for correcting the EDX data for samples with a rough surface has been developed. It is shown that the small variation in the composition of PbMoO₄, LiNbO₃, Y₃Al₅O₁₂, and Al₂O₃ samples after laser irradiation can be explained by the measurement error, related to the change in the surface roughness. At the same time, the irradiation of SrTiO₃ and Sr₂RuO₄ crystals by a YAG:Nd laser changes the chemical composition of their surface layers.