Absorption coefficient of bulk and thin film Cu2O

The optical absorption coefficient of thin film and bulk Cu2O at room temperature is obtained from an accurate analysis of their transmittance and reflectance spectra. These absorption spectra are modeled, together with the low temperature data reported in the literature, using an analytical expression to assess and quantify the role of the different absorption mechanisms. The results suggest that direct forbidden transitions and indirect transitions play an almost equally relevant role. A table of the optical constants of Cu2O single crystal is given for reference.

Graphical AbstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Room temperature absorption coefficient (α)(α) of bulk and thin film Cu2O is measured. Alpha vs. ► ℏωℏω is modeled by a superposition of direct and indirect transitions. ► Direct forbidden and indirect transitions play an almost equally relevant role. ► A table of the optical constants of Cu2O single crystal is given for reference.