• cuprous oxide;
  • Fröhlich interaction;
  • Raman spectroscopy

Anomalous low temperature behaviors in cuprous oxide (Cu2O) film grown on quartz substrate have been investigated by temperature-dependent Raman and transmittance spectra. The longitudinal optical components of two Γ15- phonon modes become sharper and more intense at a low temperature. It can be found that the highest-order electronic transition located at 6.4 eV exhibits a minimum transmittance near 200 K. Correspondingly, the variations from phonon intensity ratios reveal obvious anomalies with the decreasing temperature, indicating the existence of strong electron–phonon coupling mediated by Fröhlich interaction in the Cu2O films below the temperature of 200 K. Copyright © 2012 John Wiley & Sons, Ltd.