Thermodynamic investigations on cuprous selenide

The thermodynamic properties of electrons in cuprous selenide was studied with the help of coulometric titrations, using the solid state galvanic cell. - Pt/Cu/CuBr/Cu2-δSe/graphite, in the temperature region between 350 and 450°. The electromotive force (emf) of this cell was measured as a function of the stoichiometry of the selenide compound and the temperature. Analysis of the experimental data shows that the semiconducting properties of cuprous selenide and the change of the thermodynamic quantities with composition are only given by a change of the respective quantities of the defect electrons or of the quasifree electrons. From the electrochemical measurements besides of other quantities —the band gap energy can be calculated and is of about 0.39 eV.