Electrical and dielectric properties of amorphous GeTe alloy

Abstract

DC electrical conductivity σDC has been investigated in the range of temperature (303–393K) for bulk glass GeTe sample. The obtained results indicated that, σDC increases with temperature and there is one conduction mechanism for the investigated sample in the considered range of temperature. AC conductivity σAC(ω), dielectric constant ε0(ω) and dielectric loss ε00(ω) of GeTe alloy are examined in the range of frequency from 60Hz to 100kHz and in the range of temperature from 303K to 393K. It is found that, σAC(ω) is temperature dependent and it is proportional with ωS, 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(EF) 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 ε0(ω) and ε00(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 Wm for GeTe alloy agrees with carriers hopping theory over a potential barrier.