CRYSTAL GROWTH & DESIGN
An Interesting Correlation between Crystalline Perfection and Second Harmonic Generation Efficiency on KCl- and Oxalic Acid-Doped ADP Crystals
2008 VOL. 8, NO. 2 446–451
G. Bhagavannarayana,† S. Parthiban,‡ and Subbiah Meenakshisundaram*,‡ Materials Characterization DiVision, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110 012, India, and Department of Chemistry, Annamalai UniVersity, Annamalainagar 608 002, India ReceiVed March 3, 2007; ReVised Manuscript ReceiVed October 22, 2007
ABSTRACT: The effect of dopants (over a concentration range from 1 to 10 mol %), namely KCl and oxalic acid (C2H2O4 · 2H2O, Oxa), on the growth process, crystalline perfection, and nonlinear optical (NLO) properties of ammonium dihydrogen phosphate (NH4H2PO4, ADP) single crystals grown by a slow evaporation solution growth technique has been investigated. The high-resolution X-ray diffraction (HRXRD) studies used to evaluate crystalline perfection reveal some interesting features on the ability of accommodating the dopants by the crystalline matrix. The remarkable and systematic increase in the broadness and asymmetry of the diffraction curves as the concentration increases clearly indicates that the dopants predominantly occupied the interstitial positions in the crystalline matrix. Due to the larger size of the Oxa molecule, the crystalline matrix could not accommodate these dopants, which led to the formation of a very low angle (tilt angle
