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Electrical and Dielectric Properties of Amorphous Ge_{1}Se_{1.35}TL_{0.1} Films

100%

Abdel-Aziz M. M., Afifi M. A., Labib H. H., El-Metwally E. G.

Acta Physica Polonica A

2000

vol. 98

issue 4

393-399

The temperature dependence of the DC and AC electrical conductivity were measured for Ge_{1}Se_{1.35}Tl_{0.1} films. The value of DC electrical conduction energy ΔE_{σ} does not depend on film thickness in the investigated range with mean value of 0.72eV. The AC conductivity σ_{AC} is related to frequency by the expression σ_{AC}=Aω^{S}, where S is the frequency exponent which decreases linearly with increasing temperature. This can be explained in terms of the pair (bipolaron) correlated barrier hopping model suggested by Elliott. The frequency and temperature dependence of real and imaginary parts of the dielectric constant were studied for Ge_{1}Se_{1.35}Tl_{0.1} films. The dielectric constant (real part) and the dielectric loss (imaginary part) increase with increasing temperature and decrease with increasing frequency in the investigated range of frequency and temperature. The maximum barrier height W_{M} can be calculated according to the Giuntini equation at different temperatures. The obtained value of W_{M} is in good agreement with the theory of hopping of charge carriers over a potential barrier as suggested by Elliott in case of chalcogenide glasses.

Effect of Annealing on the AC Conductivity and the Dielectric Properties of In_{2}Te_{3} Thin Films

100%

Afifi M. A., Abd El-Wahabb E., Bekheet A. E., Atyia H. E.

Acta Physica Polonica A

2000

vol. 98

issue 4

401-409

In_{2}Te_{3} thin films were prepared by thermal evaporation technique. The composition of the films is checked by energy dispersive X-ray analysis. X-ray analysis showed that the as-deposited In_{2}Te_{3} films as well as films annealed at temperatures ≤473K have crystalline structure. The ac conductivity σ_{ac}(ω), the dielectric constant ε_{1} and the dielectric loss ε_{2} of In_{2}Te_{3} films were studied in the temperature range 303-373K and in the frequency range 100Hz-100kHz. The ac conduction activation energy ΔE_{σ}(ω) was found to be 0.065eV for the as-deposited films. The ac conductivity was found to obey the relation σ_{ac}(ω)=Aω^{s}, where s is the frequency exponent. The obtained temperature dependence of s is reasonably interpreted by quantum mechanical tunneling model. Both the dielectric constant ε_{1} and the dielectric loss ε_{2} increased with temperature and decreased with frequency in the investigated range. The frequency and temperature dependencies of σ_{ac}(ω), ε_{1}, and ε_{2} for the annealed samples have the same behavior as that for the as-deposited samples. However, values of σ_{ac}(ω), ε_{1}, and ε_{2} measured at any frequency and temperature increased with annealing temperature up to 473K. It was found also that ΔE_{σ}(ω) decreased with annealing temperature.

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2 Acta Physica Polonica A

2 2000

2 Afifi M. A.

1 Abd El-Wahabb E.

1 Abdel-Aziz M. M.

1 Atyia H. E.

1 Bekheet A. E.

1 El-Metwally E. G.

1 Labib H. H.

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Electrical and Dielectric Properties of Amorphous Ge_{1}Se_{1.35}TL_{0.1} Films

Effect of Annealing on the AC Conductivity and the Dielectric Properties of In_{2}Te_{3} Thin Films