Growth of KDP: Fe3+ Crystals from Oversaturated Aqueous Solutions

Abstract

The KH2PO4 solubility curves in pure water and in water with the addition of 50 ppm Fe3+ were refined. The KH2PO4 and KH2PO4: Fe3+ solutions stability to supercooling was evaluated by polythermal studies of the width of metastable zone. It was shown that Fe3+ addition makes the solution more stable. A series of Fe3+ doped KDP crystals were grown at different temperature and hydrodynamic regimes at supersaturation level up to 0.45. Their real structure was studied by X-ray projection topography and, as a result, the most suitable growth conditions are chosen. The transmittance spectra of prism sectors with ferric iron concentrations CFe up to 102 ppm were obtained. It was found that KDP crystals with CFe >60 ppm can be used as optical filters for suppressing transmission in UV-C and UV-B ranges.