Specific features of conductivity of γ-irradiated TlGa[Te.sub.2] crystals with nanochain structure

Temperature dependences of electrical conductivity σ(T) and current-voltage characteristics of one-dimensional TlGa[Te.sub.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.sub.∥]) and perpendicular to these nanochains ([σ.sub.[perpendicular to]])--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.sub.F], the activation energy [E.sub.a], the hop lengths R, the difference between the energies of states ΔE in the vicinity of the Fermi level, and the concentrations of deep traps [N.sub.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.sub.f], the free-path lengths λ, the Frenkel coefficients β, and the shape of the potential well in initial and irradiated (with 250 Mrad) TlGa[Te.sub.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. DOI: 10.1134/S1063782610050076