Temperature Dependence of Thermoabsorption Spectrum of Lead Sulphide

Abstract

The abasorption edge of lead sulphide has been measured over the temperature range from 300 K down to 18 K, using thermoabsorption measurements. Based upon the analysis of the thermoabsorption spectra the absorption edge energy E_g, the temperature coefficient dE_g⁄dT and the broadening factor Γ have been obtained. Typical values of E_g are as follows; E_g=0.290±0.002 eV at 20 K, E_g=0.308±0.003 eV at 85 K and E_g=0.418±0.003 eV at 292 K, respectively. The absorption edge E_g decreases linearly with decreasing temperature down to about 100 K and the temperature coefficient is 5.5×10⁻⁴ eV/deg. The temperature coefficient of the broadening factor dΓ⁄dT is about 0.3×10⁻⁴ eV/deg., less than one tenth of dE_g⁄dT. These values are discussed by comparison previously reported data.