This article is cited in 12 papers

Electronic and optical properties of semiconductors

Specific features of conductivity of $\gamma$-irradiated TlGaTe$_2$ crystals with nanochain structure

R. M. Sardarly^a, O. A. Samedov^a, A. P. Abdullayev^b, E. K. Huseynov^a, F. T. Salmanov^a, G. R. Safarova<sup>a

a</sup> Institute of radiation problems, ANAS
^b Institute of Physics Azerbaijan Academy of Sciences

Abstract: Temperature dependences of electrical conductivity $\sigma(T)$ and current-voltage characteristics of one-dimensional TlGaTe$_2$ single crystals subjected to various doses of $\gamma$-ray radiation in both geometries of the experiment-along nanochains parallel to the tetragonal axis of the crystal $(\sigma\parallel)$ and perpendicular to these nanochains $(\sigma\perp)$-are studied. It is shown that the dependence $\sigma(T)$ 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 $N_{\mathrm{F}}$, the activation energy $E_{\mathrm {a}}$, the hop lengths $R$, the difference between the energies of states $\Delta E$ 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 $\lambda$, the Frenkel coefficients $\beta$, 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.

Received: 12.10.2009
Accepted: 20.10.2009

 English version: Semiconductors, 2010, 44:5, 585–589

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