Influence of l-alanine doping on crystalline perfection, SHG efficiency, optical and mechanical properties of KDP single crystals

• Published in: Physica. B, Condensed matter Vol. 406; no. 18; pp. 3392 - 3397
• Main Authors: Shakir, Mohd, Ganesh, V., Riscob, B., Maurya, K.K., Wahab, M.A., Bhagavannarayana, G., Kishan Rao, K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.09.2011; Elsevier
• Subjects: Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystal structure; Crystals; Diffraction; Doping; Exact sciences and technology; Frequency conversion ; harmonic generation, including high-order harmonic generation; Fundamental areas of phenomenology (including applications); Grain boundaries; Growth from solutions; High-resolution X-ray diffraction; Nonlinear optic materials; Nonlinear optics; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optics; Other nonmetals; Physics; Single crystal growth; Single crystals; Visible and ultraviolet spectra; X-rays; Growth from solutions; High-resolution X-ray diffraction; Nonlinear optic materials; Single crystal growth; Second harmonic generation; Raman spectra; Vickers hardness; Impurity density; Doping; Amino acids; XRD; Lattice parameters; Crystal perfection; Monocrystals; KDP; Alanines; Crystal growth from solutions; Ultraviolet visible spectrum
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2011.06.005

Pure and l-alanine (LA) doped single crystals of potassium dihydrogen orthophosphate (KDP) were grown by slow evaporation solution technique (SEST) in aqueous solution at ambient temperature. Powder X-ray diffraction study was done to confirm the crystal system and lattice parameters of KDP. No additional phases were observed at all doping concentrations (1–7.5 mol%), which was further confirmed by FT–Raman spectroscopy analysis. The influence of LA doping on the crystalline perfection was assessed by high-resolution X-ray diffractometry (HRXRD) analysis. HRXRD studies revealed that the grown crystals could accommodate LA at the interstitial positions in the crystalline matrix of KDP up to some critical concentration without any deterioration in the crystalline perfection. Above this concentration, very low angle structural grain boundaries were developed and it seems that the excess LA above the critical concentration was segregated along the grain boundaries. The SHG efficiency was measured using the Kurtz powder technique. The relative SHG efficiency of the crystals was found to be increased with doping concentration up to 5 mol% and above this it decreases. Optical transmission study also revealed the same behavior with enhancement up to 5 mol% concentration and later decreased. The hardness values were found to be increased by increasing the doping concentration.