Immersing ampoule Sankaranarayanan–Ramasamy (ISR) method: Unidirectional high-quality single crystal growth

Abstract

The optically good quality organic 2-aminopyridinium 4-nitrophenolate 4-nitrophenol (2AP4N) single crystal (length 120 mm and diameter 15 mm) was grown by a novel Immersing ampoule Sankaranarayanan–Ramasamy (ISR) method. The water covered completely the ampoule containing growth solution in the unidirectional method for the first time in the literature. The ampoule was specially designed for the growth of good quality and bulk size unidirectional single crystals by slow cooling condition. The unwanted temperature gradient developed on the solution surface was completely avoided, hence the secondary nucleation developed on top of the ampoule is avoided. The growth apparatus and optimizations parameters have been made simpler compared to the conventional SR method. Growth direction parallel to the gravity direction can be easily achieved, hence slanted growth could be avoided within the ampoule and also linear transportation of embryos from solution to crystal-solution interface is achieved. The ISR method-grown single crystal was subjected to various characterizations. The optical behavior of the grown crystal was analyzed by UV–Vis NIR spectrophotometer. The optical homogeneities of the single crystal have been analyzed by birefringence measurement. The growth of 〈001〉 direction was confirmed by the PXRD analysis. The crystalline perfection of different growth portions (bottom, middle and top) was analyzed by HRXRD measurement. The full-width at half maximum (FWHM) values of various regions, indicate that the whole grown crystal has high crystalline perfection and is optically homogeneous. The new crystal growth ISR method has been introduced and also the various studies reveal that the ISR method grown single crystals are favorable for high performance optical device applications.