The effect of metallic ions on tapering phenomenon of DKDP crystals and its elimination

Abstract The anomalous wedge‐like shape of KH2PO4‐type single crystal, also called tapering, is discussed in this paper. DKDP single crystals grew on seeds from the solutions containing high concentrations of Al3+, Fe3+ and Cr3+ impurities. The tapering phenomenon occurred on the prismatic {010} faces, and the tapering angle θ was nearly measured as 10°. We adjusted the pD value of the solution from 3.0 to 4.2 by adding K2CO3, the tapering angle of DKDP crystal grown from the same solution at same supercooling was reduced to 0°. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)