Observations of Dislocations in Ammonium Dihydrogen Phosphate: Production of Dislocation-Free Crystals

Abstract

The results of etch-pit and diffraction topographic studies on ammonium dihydrogen phosphate (ADP) are reported. These studies were carried out on specimens sectioned by abrasive wheel and string-saw from large single crystals grown from aqueous solution. The two characterization methods are shown to be in approximate one-to-one correspondence in the case of sections produced by abrasive sawing. Absence of both etch pits and topographic images in sections made by string-sawing of material well removed from the seed region is taken to indicate that this material is dislocation-free. Preliminary results on the plasticity of ADP are reported.