Regular Article

Electrical and dielectric properties of amorphous GeTe alloy

Physics Department, Faculty of Education, Ain Shams University, Roxy, Cairo 11757, Egypt

^a e-mail: eg_elmetwally@yahoo.com

Received: 2 October 2019
Received in final form: 7 November 2019
Published online: 18 December 2019

Abstract

DC electrical conductivity σ_DC has been investigated in the range of temperature (303–393 K) for bulk glass GeTe sample. The obtained results indicated that, σ_DC increases with temperature and there is one conduction mechanism for the investigated sample in the considered range of temperature. AC conductivity σ_AC(ω), dielectric constant ε′(ω) and dielectric loss ε′′(ω) of GeTe alloy are examined in the range of frequency from 60 Hz to 100 kHz and in the range of temperature from 303 K to 393 K. It is found that, σ_AC(ω) is temperature dependent and it is proportional with ω^S, where the frequency exponent S < 1 and inversely proportional with temperature, this indicates that the hopping process is the most influential mechanism. Values of the density of localized states at Fermi level N(E_F) for the investigated composition were found to be within the range ( ≈10²⁹ eV⁻¹ cm⁻³) and increased with frequency and temperature. The obtained results of dielectric measurements show that ε′(ω) and ε′′(ω) are directly proportional with temperature and inversely proportional with frequency. We discussed these results using the model of correlated barrier hopping (CBH). The calculated value of maximum height of barrier W_m for GeTe alloy agrees with carriers hopping theory over a potential barrier.