Electroreflection of Amorphous Selenium

Abstract
On amorphous selenium layers electroreflectance has been measured in the energy range from 1.7 to 4.2 eV. Only one relatively broad structure was found near 2.1 eV, i.e. below the electrical band gap and the photoconduction edge. It has a temperature coefficient of about −2.7 × 10−4 eV/°K. The explanation of this structure by a Frenkel type exciton seems to be the most plausible.