Near infrared optical and photoelectric properties of Cu2O. III. Interpretation of experimental results

Experimental results given in Part I and II are interpreted with the help of a band scheme including five energy levels: β (1.91 eV above the VB, due to exciton—neutral acceptor complexes creation with 0.1 eV binding energy), A (0.55 eV above the VB, copper vacancies V), B (0.76 eV above A, [V—V] vacancy associations), C (0.97 eV above A, [VCu—VCu] vacancy associations) and D (0.38 eV below the CB, due to oxygen vacancies V+O). The strongest absorption bands, as well as the minima in the photoconductivity spectrum are explained by optical transitions from A to B and C levels. The defect density responsible for the level C is about 1017 cm−3. This scheme is consistent with results obtained by other authors on the electrical properties and the luminescence of Cu2O.