Electronic structure modifications of cuprous-oxide films by ions

We have investigated irradiation effects with 100 keV Ne and N ions on optical properties and atomic structure of cuprous oxide (Cu2O). Cu2O films were prepared on MgO substrates at 700 °C by using a RF-magnetron-sputter deposition method. X-ray diffraction shows that the films are polycrystalline with (111) orientation and disordering by ion irradiation has been observed. The composition is found to be nearly stoichiometric before and after ion irradiation by means of Rutherford backscattering spectroscopy. Optical absorbance shows small but visible oscillations in the spectrum near the absorption edge (i.e., in the wavelength of 200 to 500 nm), and ion irradiation reduces the oscillation. Modifications of bandgap and surface morphology under ion irradiation have been described.