Growth and annealing of CdZnTe:Cl crystals with different content of Zn for nuclear detectors

• Published in: Semiconductors (Woodbury, N.Y.) Vol. 43; no. 10; pp. 1379 - 1386
• Main Authors: Zelenina, N. K., Karpenko, V. P., Matveev, O. A., Sedov, V. E., Terentyev, A. I., Tomasov, A. A.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-10-2009
• Subjects: Fabrication; Magnetic Materials; Magnetism; Physics; Physics and Astronomy; Testing of Materials and Structures; Treatment; 78.55.Et; 61.72; 72.40.w; 71.55.Gs; 07.85.Fv
• ISSN: 1063-7826; 1090-6479
• DOI: 10.1134/S1063782609100224

The methods of photoluminescence, Hall effect, extrinsic photoconductivity, and transit time have been used to study the influence of the pressure of cadmium vapor (
P
Cd
) in the course of postgrowth annealing of ingots and annealing of semi-insulating crystals Cd
1 −
x
Zn
x
Te:Cl (
x
= 0.005, 0.01, 0.05, 0.1) on compensation of conductivity of the material used for fabrication of nuclear detectors. It is established that free holes are captured by acceptor levels of both cadmium and zinc vacancies. Studies of electrical properties of crystals after annealing at various pressures of cadmium vapors showed that, at low zinc content (
x
= 0.005 and 0.01), the determining effect on the conductivity compensation in Cd
1 −
x
Zn
x
Te:Tl is exhibited by the
V
Cd
−2
cadmium point defects. However, even at the zinc content
x
≥ 0.05, it is necessary to take into account the effect of zinc point defects
V
Zn
−2
; in order to obtain such crystals with the best transport characteristics it is necessary to control not only the pressure of cadmium vapors in the course of growth of the material but also the zinc vapor pressure. It is established that it is possible to control the main electrical characteristics of the semi-insulating material with the zinc content
x
≤ 0.01 grown by horizontal planar crystallization and designed for nuclear detectors by varying the pressure of cadmium vapors in the course of the postgrowth annealing.