In situ Observation of the Growth of KDP Crystal (101) Faces Doped by Na₃(PO₃)₃

The effect of Na-3(PO3)(3) on the growth of KDP crystal (101) faces was studied by the Michelson interference technique and atomic force microscopy. The experimental results show that the growth rates were near zero at low supersaturation when Na-3(PO3)(3) was doped into solution, i.e., there was a supersaturation interval similar to the "growth dead zone". The growth rates began to increase rapidly as the supersaturation crossed the "growth dead zone" and continued to increase. The "growth dead zone" increased as the doping concentration was increased. In addition, the anisotropy of growth hillocks decreased and the competition of growth hillocks became more intense when the doping concentration of Na-3(PO3)(3) was gradually increased in solution at confirmed supersaturation. The calculated surface free energies of three adjacent planes show that they increased with the increase of doping concentration and always alpha(I), alpha(II) > alpha(III).