Electric field distribution around cadmium and tellurium inclusions within CdTe-based compounds

• Published in: Journal of crystal growth Vol. 533; p. 125486
• Main Authors: Wardak, Aneta, Witkowska-Baran, Marta, Szot, Michał, Kochanowska, Dominika, Witkowski, Bartłomiej S., Avdonin, Andrei, Mycielski, Andrzej
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-03-2020; Elsevier BV
• Subjects: A1. Optical microscopy; A1. Volume defects; A2. Growth form melt; B2. Semiconducting II-VI materials; B3. Nuclear detectors; Cadmium; Cadmium compounds; Cadmium tellurides; Chemical composition; Cracks; Crystal defects; Electric fields; Inclusions; Manganese; Morphology; Selenium; Tellurium; Twin boundaries; Zincblende; A2. Growth form melt; B2. Semiconducting II-VI materials; A1. Optical microscopy; A1. Volume defects; B3. Nuclear detectors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2020.125486

•Chemical composition and morphology of Cd and Te inclusions are linked.•Cd inclusion micro affects the crystal lattice, unlike to Te one.•Electric field distribution is shown around grouped or isolated Cd and Te inclusion.
We examine two kinds of volume defects in CdTe-based compounds grown from the melt: cadmium and tellurium inclusions. We have determined their chemical composition by energy-dispersive X-ray spectroscopy and their internal morphology by infrared transmission microscopy. The tellurium inclusions are spheroidal/polyhedral, while the cadmium ones appear star-like. The core size of both the tellurium and the cadmium inclusions is 5–8 μm. Cadmium inclusions cause micro cracks so that they create star-like defects the size of which is about ten times bigger than the inclusions themselves. Each pair of branches in the star-shaped defect we associate with the three easy-cleavage planes (1 1 0) of the zinc blende structure. Using Pockels imaging we have investigated how tellurium and cadmium inclusions influence the electric field distribution in CdTe compounds, which is an important issue for nuclear detectors. Only tellurium inclusions distributed along a continuous plane have an impact on the internal electric field. Neither the separated tellurium inclusions nor the separated cadmium inclusions influence the internal electric field. Crystals of (Cd,Mn)(Te,Se) have a high concentration (104–105 cm−3) of both types of inclusions. In (Cd,Mg)Te there are numerous twin boundaries decorated with tellurium inclusions. Among the studied compounds, (Cd,Mn)Te has the highest quality.