Raman Back-Scattering Spectroscopy of KDP Crystal Doped by Fe+3 at Low Temperatures in the Lower Hydrogen Bonds Region

摘要

Single crystals of KDP, potassium dihydrogen phosphate, were grown from supersaturated solutions containing different trivalent metallic ions as dopants. The growth rates of (100) and (101) faces were faster than other faces. Some especial dopants commonly affect the growth rate of crystal. Such impurities can be metallic ions such as Fe+3, Al+3 or Cr+3. There are many studies concerning the effect of dopants on the growth rate of KDP single crystals. Impurities produce a variety of crystals of different apparent shapes. The mechanism of crystal growth with different dopants was successfully explained by many researches. However, there is a clear lack of experimental data at low temperature Raman spectroscopy. Accordingly, the objective of this study is to show the effects of metallic ions in KDP crystal growth from a saturated solution doped by Fe+3. The behavior of the Raman scattering spectra at lower temperatures down to 10 K of the grown KDP crystals with Fe+3 doping at spectral region up to 1500 cm?1 has been considered. The main emphasis of this paper will be concentrated on the modes behavior related to hydrogen bond modes and also soft modes under the effect of Fe+3 doping. The overall results reveal that that some of these Raman active peaks shift in frequency and they become much more intense at low temperatures.