A consistent approach towards Bi doping mechanism in chalcogenide glasses from Cp measurement in Ge–Se–Te–Bi system

In this paper, we are proposing a consistent approach to understand the mechanism of Bi doping in Ge–Se glasses by carrying out specific heat (Cp) measurement in Ge20Se70−xTe10Bix system for 0≤x≤11. The two softening temperatures exhibited by heat-treated samples are explained on the basis of ‘microscopic phase separation’. The minimum in ‘configurational heat capacity’ (ΔCp) at x=7.5 for as-prepared glasses is related to be a feature of chemical threshold. A supporting evidence for three-fold coordination for Bi in line with the earlier structural studies is deduced.