Defect segregation in CdGeAs2

• Published in: Journal of crystal growth 2001-05, Vol.225 (2-4), p.440-444
• Main Authors: Schunemann, Peter G, Setzler, Scott D, Pollak, Thomas M, Ptak, Aaron J, Myers, Thomas H
• Format: Article
• Language: English
• Subjects: A1. Directional solidification; A1. Point defects; A1. Segregation; A2. Gradient freeze technique; B1. Chalcopyrites; B2. Nonlinear optical materials; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Growth from melts; zone melting and refining; Materials science; Methods of crystal growth; physics of crystal growth; Nonlinear optical crystals; Optical materials; Optics; Physics; Point defects (vacancies, interstitials, color centers, etc.) and defect clusters; Structure of solids and liquids; crystallography
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(01)00912-5

Increased axial temperature gradients and growth rates have resulted in segregation of unwanted absorbing defects to the edges of CdGeAs2 single crystals produced by the horizontal gradient freeze technique. Long-wavelength infrared imaging of polished boules revealed a “clear” central core with absorption losses 26 times lower than in the darker edge regions. This pronounced segregation is attributed to the preferred incorporation of native defects at facets that form near the side walls of the horizontal boat. EPR, GDMS, and Hall effect analysis were used to characterize the nature of these defects.