Temperature Dependence of Absorption Coefficient in Silicon of Lower Purity

V. Schlosser

• Institut für Festkörkerphysik der Universität Wien, A-1090 Wien, Austria and
  Ludwig Boltzmann Institut für Festkörperphysik, A-1060 Vienna, Austria

ABSTRACT: We have derived the absorption coefficient of high purity and lower purity p-Si as a function of temperature between 80 K and 420 K from transmission measurements in the photon energy range of 1.1 eV to 1.5 eV. From these data the temperature dependence of the indirect gap was calculated. A significant difference between both samples was observed. An additional term of the absorption in silicon which is not due to the fundamental transition increases linearly with decreasing temperature. It was found to be equal for both samples as long as the absorption coefficient is in the range between 100 cm^-1 and 300 cm^-1 and the temperature is less than 300 K.