Electrical and dielectric properties of amorphous Ge1Se1.35Tl0.1 films

The temperature dependence of the DC and AC electrical conductivity were measured for Ge1Se1.35Tl0.1 films. The value of DC electrical conduction energy DeltaE(sigma) does not depend on film thickness in the investigated range with mean value of 0.72 eV. The AC conductivity sigma (AC) is related to frequency by the expression sigma (AC) = A omega (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 Ge1Se1.35Tl0.1 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 st 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.