Effects of the Structure of Cu(II) Complex in Etchants on the Dislocation Etch Pit Morphology of Lithium Fluoride

Abstract

A new etchant, containing cupric chloride, is described for producing dislocation etch pits on lithium fluoride. It is shown that etch pits with edges parallel to ⟨100⟩ and ⟨110⟩ directions on the (100) surface of lithium fluoride can be obtained by using this etchant. The morphology of etch pits, produced by solutions varying the concentration of cupric chloride, pH, the undersaturation and the concentration of chloride ion, has been investigated by the differential interference microscopy and the molecular structure of Cu(II) complex in etchants by the ultraviolet visible absorption spectra. The reason for the change in the etch pit morphology is explained on the basis of the changes in the structure of Cu(II) complex in solutions and in the movement velocity of kinks and steps on the surface of lithium fluoride.