Science and Technology 2012, 2(5): 109-113 DOI: 10.5923/j.scit.20120205.01 Study on Growth Habit, SHG and Thermal Properties of Urea Phosphate Doped KDP Crystals G. G. Muley Department of Physics, Sant Gadge Baba Amravati University, Amravati, 444602, (M S) India Abstract Pure and doped with Urea Phosphate single crystals of Potassium Dihydrogen Phosphate (KDP) were grown by the low temperature solution growth method, adopting the technique of slow evaporation of the solvent for nonlinear optical applications. The change in the growth habit of the doped KDP crystals has been reported. The study confirms the decrease in the growth rate along c-axis with increasing the dopant concentration. The doping of the Urea Phosphate in the grown crystal has been confirmed qualitatively by the FT-IR spectroscopy. Form the UV-Visible-NIR transmission study; it was observed that the transparency of the crystal increases with dopant concentration. Thermo Gravimetric Analysis shows that the thermal stability of the crystal decreases with dopant concentration. The crystal structure of doped crystal was determined from Powder X-Ray diffraction studies. The improvement in Second Harmonic Generation efficiency of doped crystal has also been reported. Keywords NLO crystal, Growth habit, Second harmonic generation, XRD study 1. Introduction Potassium Dihydrogen Phosphate (KDP) crystal is most widely used and thoroughly studied nonlinear optical (NLO) crystal. The attempts have been made to modify the proper- ties favorable for NLO applications and growth rate of the KDP crystal by either changing the growth conditions or by adding different impurities[1-6]. The Ethylenediamine tetra acetic acid (EDTA) inhibits growth of KDP and acts as scattering centers in grown crystals[7] while on the other side it prevents number of nucleation’s, increasing metasta- ble zone width, which helps in growing big size good qual- ity crystal[8]. Azo-organic dye Amaranth gets absorbed and colors the pyramidal section (1 0 1) of the crystals and Sunset yellow FCF modifies the crystal habit and color of KDP. It decreases size of prismatic section of the crystal[9]. The increase in mean growth rate along the[001] direction has been reported with an increase in the concentration of trivalent impurity Cr(III) in the KDP solution while the growth rate along[100] direction is not altered[10]. A simi- lar effect of Fe(III) and Cr(III) on the growth rate of KDP crystals has been reported by Owczarek and Sangwal[11]. Amino acids have very large optical nonlinearity, assigned to the chiral structure, used by many workers to improve the NLO, optical, thermal and mechanical properties of KDP using as a dopant[12,13]. * Corresponding author: gajananggm@yahoo.co.in (G. G. Muley) Published online at http://journal.sapub.org/scit Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved Urea has been reported as a NLO material. Although it’s optical and mechanical properties are comparable to those of KDP, but its crystallization and handling is rather diffi- cult as it is highly hygroscopic. Different derivatives of urea have been studied for NLO applications. Some of them found useful for NLO applications[6,14-18]. The Urea and Urea derivates Thiourea, N’N dimethyl Urea have been tried as a dopent in KDP[19-22]. As KDP is being widely used in NLO applications and demands to modify its properties, the research work on the modifications of the optical, thermal, mechanical and NLO properties and the growth rate of the KDP crystal by using different dopants is still going on[23-25]. The urea and urea derivatives have high NLO efficiency and can be used as dopant to modify the properties of KDP crystal. In the pre- sent work, an attempt has been made to catch the properties of Urea derivative; Urea Phosphate and add it with KDP to investigate the effects. The growth of Urea Phosphate doped KDP crystals and their characterizations have been presented. Improvement in the SHG efficiency has been reported. Modification in the growth habit has also been observed. 2. Experimental 2.1. Bulk Crystal Growth The solubility’s of the pure (KDP) and 2mol%, 4mol% and 6mol% Urea Phosphate doped KDP (KU1, KU2 and KU3 respectively) crystals were measured gravimetrically in double distilled water in the temperature range 30-60℃