Features of the Cluster-Ion Treatment of the Surface of a KGd(WO4)2:Nd Single Crystal

The features of the surface treatment of potassium-gadolinium-tungstate single crystals doped with neodymium ions by low- and high-energy argon cluster ions are considered. Two radically different treatment modes are employed: the low-energy mode for more efficient smoothing of the surface and high-energy for more effective etching of the target. The topography of the target surface is analyzed before and after cluster-ion treatment using atomic force microscopy. It is shown that treatment in the low-energy mode smoothes out irregularities on the target surface formed by chemical and mechanical polishing at an etching depth of less than 100 nm. A comparison is made of the root-mean-square roughness and total roughness of the initial and treated surfaces of potassium-gadolinium tungstate doped with neodymium ions. Survey X-ray photoelectron spectra of the initial surface of a KGd(WO4)2:Nd single crystal and after cluster-ion treatment in various modes are presented. It is demonstrated that the intensities of the potassium and gadolinium peaks decrease after cluster-ion treatment in both modes. A significant decrease in the concentration of potassium atoms in the surface layer of the target is explained by the preferential 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.