Specific features of conductivity of γ-irradiated TlGaTe2 crystals with nanochain structure

• Published in: Semiconductors (Woodbury, N.Y.) N.Y.), 2010-05, Vol.44 (5), p.585-589
• Main Authors: Sardarli, R. M., Samedov, O. A., Abdullayev, A. P., Huseynov, E. K., Salmanov, F. T., Safarova, G. R.
• Format: Article
• Language: English
• Subjects: Electrical and Optical Properties of Semiconductors; Magnetic Materials; Magnetism; Physics; Physics and Astronomy
• ISSN: 1063-7826; 1090-6479
• DOI: 10.1134/S1063782610050076

Temperature dependences of electrical conductivity σ( T ) and current-voltage characteristics of one-dimensional TlGaTe 2 single crystals subjected to various doses of γ-ray radiation in both geometries of the experiment-along nanochains parallel to the tetragonal axis of the crystal (σ | ) and perpendicular to these nanochains (σ ⊥ )-are studied. It is shown that the dependence σ( T ) measured in the ohmic region of the current-voltage characteristic is the shape typical of the hopping mechanism and can be described in terms of the Mott approximation. The values of the densities of localized states N F , the activation energy E a , the hop lengths R , the difference between the energies of states Δ E in the vicinity of the Fermi level, and the concentrations of deep traps N t are determined. The current-voltage characteristics in the region of a more abrupt increase in the current are also studied. It is shown that this region of current-voltage characteristics is described in the context of the Pool-Frenkel thermal-field effect. Concentrations of ionized centers N f , the free-path lengths λ, the Frenkel coefficients β, and the shape of the potential well in initial and irradiated (with 250 Mrad) TlGaTe 2 crystals are determined. It is shown that anisotropy of electrical conductivity changes under the effect of irradiation, which brings about translational ordering of nanochains.