Defect segregation in CdGeAs2

Increased axial temperature gradients and growth rates have resulted in seg regation of unwanted absorbing defects to the edges of CdGeAs2 single cryst als produced by the horizontal gradient freeze technique. Long-wavelength i nfrared imaging of polished boules revealed a "clear" central core with abs orption losses 76 times lower than in the darker edge regions. This pronoun ced segregation is attributed to the preferred incorporation of native defe cts at facets that form near the side walls of the horizontal boat. EPR, GD MS, and Hall effect analysis were used to characterize the nature of these defects. (C) 2001 Elsevier Science B.V. All rights reserved.