Compensation effect in undoped polycrystalline CdTe synthesized under nonequilibrium conditions

• Published in: Physics of the solid state Vol. 53; no. 8; pp. 1554 - 1563
• Main Authors: Bagaev, V. S., Klevkov, Yu. V., Kolosov, S. A., Krivobok, V. S., Shepel’, A. A.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-08-2011; Springer
• Subjects: Activation energy; Electric properties; Physics; Physics and Astronomy; Semiconductors; Solid State Physics; Deep Center; Electrical Resistivity; Persistent Photoconductivity; Longitudinal Optical; Intrinsic Point Defect
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783411080051

The compensation effect has been revealed in undoped polycrystalline CdTe synthesized during rapid crystallization. The revealed effect leads to an increase in the electrical resistivity to 10
8
–10
10
Ω cm at a background impurity concentration of ∼1015 cm
−3
(Ga
Cd
and Cl
Te
donors, unidentified acceptors). For some samples, this effect is accompanied by the appearance of persistent photoconductivity, which disappears at a temperature of ∼200 K. It has been shown that all the polycrystals studied are characterized by a three-level compensation mechanism in which the fundamental properties of the material are determined by deep donors and/or acceptors with a concentration of 10
12
cm
−3
. Depending on the specific growth conditions, the electrical resistivity at room temperature is determined by deep centers with activation energies of 0.59 ± 0.10 and 0.71 ± 0.10 eV, which are supposedly related to intrinsic point defects, and deep centers with activation energies of 0.4 ± 0.1 eV, which belong to the
DX
center formed by the Ga
Cd
donor.