Chalcogenide Se50Te20S30 thin film of different
thickness was deposited using thermal evaporation technique.
The thermogram of the chalcogenide bulk Se50-
Te20S30 was obtained using a differential scanning
calorimetry (DSC) with heating rate of 7.5 K/min. The
glass transition temperature Tg, crystallization temperature
Tc and peak crystallization temperature Tp were identified.
The X-ray diffraction (XRD) examination indicates the
amorphous nature of the as-deposited film and polycrystalline
structure of the thermal annealed ones. The dark
electrical resistivity (q) measurements were taken in temperature
range (300–500 K) and thickness range
(200–450 nm). Analysis of the electrical resistivity results
revealed two types of conduction mechanisms: conduction
due to extended states in the temperature range (T[Tc)
and variable range hopping in the temperature range
(TTc). The effect of the heat treatment and thickness on
the density of localized states at the Fermi level N(EF) and
hopping parameters were studied.