Effect of EDTMPA on the quality of KDP crystal

Abstract

The pure and ethylene diamine tetra methylene phosphonic acid (EDTMPA) doped potassium dihydrogen phosphate (KH2PO4, KDP) crystals were grown by cooling aqueous solution method. In the present paper, the effect of EDTMPA on the growth rate, phase purity, transmittance, thermal stability and dislocations of KDP crystal were studied. The structure of KDP crystals grown from doped solution do not change from the X-ray diffraction pattern, and there exists an improvement in crystallinity in some circumstances; the Fourier transform infrared spectra indicated that EDTMPA additives did not enter into the KDP crystal; compared with undoped situation, the transmittance of crystals in the ultraviolet band decreases with 200 ppm and 400 ppm EDTMPA doped, it is significantly improved with 600 ppm and 800 ppm additives doped; EDTMPA additives has a little impact on the thermal stability of KDP crystals, the weight loss of KDP crystals decreases with the addition of EDTMPA; From the observation of etch pits of KDP crystals by optical microscope, high doping concentrations reduce the dislocation density of KDP crystal to some extent.