Homogeneity characterization in AgGaGeS4, a single crystal for nonlinear mid-IR laser applications

• Published in: Journal of crystal growth Vol. 548; no. 125814; pp. 125814 - 7
• Main Authors: Rame, Jérémy, Petit, Johan, Boivin, Denis, Horezan, Nicolas, Melkonian, Jean Michel, Godard, Antoine, Viana, Bruno
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2020; Elsevier BV; Elsevier
• Subjects: A1 Volume defects; A2 Bridgman technique; B1 Sulfides; B2 Nonlinear optic materials; Chemical analysis; Chemical Sciences; Conversion; Crystal defects; Crystal growth; Crystallization; Engineering Sciences; Homogeneity; Inhomogeneity; Laser applications; Laser beams; Optical frequency; Optical properties; Physics; Single crystals; Volatility; B1 Sulfides; B2 Nonlinear optic materials; A2 Bridgman technique; A1 Volume defects; VOLUME DEFECTS; BRIDGMAN TECHNIQUE; SULFIDES; MONOCRISTAL; DEFAUTS; NONLINEAR OPTIC MATERIALS; MEB; DEFAUT
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2020.125814

•A precise, large crystal area, high resolution, chemical analysis helps to understand volume defects origins.•Bridgman grown AgGaGeS4 shows chemical trails.•Depletion of GeS2 is responsible of chemical gradients in AgGaGeS4. Single crystal quality is a key issue for optical applications. Indeed, in optical frequency conversion processes, defects in single crystals can drastically decrease the conversion yield. The study of the quality of an AgGaGeS4 single crystal is presented in this work. Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-Ray Spectroscopy (EDS) was used to perform a chemical analysis mapping of a large size single crystal cut (surface 26 × 20 mm2). Chemical inhomogeneity was found along the crystal growth axes and confirmed by optical characterization showing laser beam perturbations. Compounds volatility, lack of melt homogenization and instability of crystallization front might explain this chemical inhomogeneity. Solutions to improve the crystal growth process and enhance the crystal’s quality are finally proposed.