The
kinetics of phase transitions in bismuth-modified selenide
glasses AsxSe100-x-yBiy as studied by differential
thermal analysis and exoelectron emission
Chem.
Met. Alloys 4 (2011) 22-25
https://doi.org/10.30970/cma4.0140
Czesław GÓRECKI, Tadeusz GÓRECKI
The kinetics of the glass transition (retrification) in bismuth-modified selenide
glasses AsxSe100-x-yBiy (x =
10.2, 8, 6 and y = 0, 2, 4) have
been investigated by parallel differential thermal analysis (DTA) and exoelectron emission (EEE) measurements. EEE is a
surface effect connected with structural transformations in the surface layer,
whereas the DTA measurements give information about
transformations occurring in the bulk of the sample. It was found that the
phase transitions occurring in the investigated selenide
glasses are evidenced by anomalies in the temperature dependence of both the EEE intensity and DTA curves. Consequently,
the validity of the DTA and EEE
techniques for studies of phase transitions in vitreous chalcogenide
semiconductors has been demonstrated. Admixture of bismuth causes a significant
lowering of the temperature of the retrification
process, both in the surface layer and in the bulk. It causes a decrease of the
activation energy for the retrification process on the
surface as well as in the bulk, reducing the thermal stability of the
investigated materials. A more detailed comparison of the DTA
traces indicates that the areas under the endotherms
of the samples containing Bi are systematically (by about 36 %) lower
than those of the corresponding samples without Bi.
Ozawa plots for the
surface (EEE) and volume (DTA)
retrification temperatures of the As6Se90Bi4
glass.
Keywords
Chalcogenide glasses / Exoelectron
emission / Activation energy / Retrification