Abstract: A technique includes fabricating a layered precursor including: depositing a first film including a first indium gallium selenide compound on a substrate; then depositing a second film including a CuSe compound; then heating the substrate, the first film and the second film to convert the CuSe compound in the second film to a Cu2-xSe (0.2=?x?1) compound; then reactively depositing a third film including a second indium gallium selenide compound to convert the first film, the second film and the third film into a CIGS absorber film; and forming nanoscale morphological asymmetries in the CIGS absorber film, wherein a surface portion of the CIGS absorber film has a distribution of grain sizes with gaps between most of their surface area characterized by reentrant angles which effectively trap light.