Features of cluster ion treatment of the surface of KGd(WO<sub>4</sub>)<sub>2</sub>:Nd single crystal

Abstract

The features of the surface treatment of single crystals of potassium gadolinium tungstate doped with neodymium ions with low- and high-energy cluster argon ions are considered. Two radically different treatment modes were used: low-energy for more efficient surface smoothing and high-energy for more efficient target etching. Using atomic force microscopy, the topography of the target surface was analyzed before and after cluster ion treatment. Treatment in a low-energy mode was shown to smooth out irregularities on the target surface formed by chemical-mechanical polishing at an etching depth of less than 100 nm. The root-mean-square roughness and maximum height difference of the initial and treated surfaces of potassium gadolinium tungstate doped with neodymium ions were compared. Survey X-ray photoelectron spectra of the initial surface of a KGd(WO4)2:Nd single crystal and after the cluster ion treatment in different modes are presented. The intensities of the potassium and gadolinium peaks were shown to decrease after cluster ion treatment in both modes. A significant decrease in the concentration of potassium atoms in the subsurface layer of the target is explained by the predominant sputtering of potassium as a lighter chemical element. The mutual decrease in the concentrations of gadolinium and potassium atoms can be explained by the weak bonds of these atoms in the lattice of the KGd(WO4)2:Nd single crystal.