Ac Conductivity and Dielectric Properties of Amorphous Ge₁₅Se₆₀X₂₅( X = As or Sn) Films

Abstract

The ac conductivity and dielectric properties of Ge 15 Se 60 X 25 (X = As or Sn) thin films are reported in this paper. The thin films were deposited by thermal evaporation at 10 −5 Torr pressure. The films were well characterized by X-ray diffraction, differential thermal analysis and energy dispersive X-ray spectroscopy. The ac conductivity was measured over temperature range 303-413 K and frequency range 10 2 -10 5 Hz. The frequency dependence of the ac conductivity was found to be linear with slope which lies very close to unity and is independent of temperature. This behavior can be explained in terms of the correlated barrier hopping between centers forming intimate valence alternation pairs. Values of the dielectric constant ε 1 were found to decrease with frequency and increase with temperature. The maximum barrier height W m for each sample, which was calculated from the dielectric measurements according to the Guinitin equation, agrees with the theory of hopping of charge carriers over potential barrier as suggested by Elliott in case of chalcogenide glasses. The density of localized state near the Fermi level was estimated for the studied films.

AC Electrical Conductivity and Dielectric Properties of Perovskite (Pb,Ca)TiO3Ceramic

“…This behavior is similar to that obtained in amorphous semiconductors and glasses [23]. It is also observed from Fig.…”

Effect of Annealing Temperature on the Electric and Dielectric Properties of Se70Te15Bi15Films

“…This mechanism is due to hopping between states near the mobility edges where the density of states is not constant. The same results are obtained for other chalcogenide compositions [27]. The above relation is dierent from the nonlinear relation obtained for some compositions [28,19].…”

“…7. This may be attributed to the increase of applied eld frequency which enhances the electronic jump between localized states [27]. The same behavior was obtained for ∆E σ (DC) with annealing temperature as shown in Table II.…”

“…Accordingly, the dielectric loss at low and moderate frequencies is characterized by high values of ε 2 due to the contribution of ion jump and conduction loss of ion migration, in addition to the ion polarization loss. However, at high frequencies, the ion vibrations may be the only source of dielectric loss [27]. It is clear also that at any frequency ε 2 increases with increasing working temperatures, which can be interpreted by Stevels [33], who divided the relaxation phenomenon into three parts, conduction losses, dipole losses and vibrational losses.…”

Mechanical and Dielectric Properties of InTe Crystals

“…The AC conductivity and dielectric properties of Sb 2 Te 3 thin films have been investigated in the frequency range, 0.4 -100 kHz as a function of temperature [9]. Hegab et al [10] have evaluated the dielectric properties and frequency dependence of AC conductivity of amorphous Ge 15 Se 60 X 25 (X = As or Sn) thin films deposited by thermal evaporation. Bose and Purkayastha [11] have determined the dielectric constants of In 2 Te 3 crystals grown by the Bridgman method.…”