Structural and optical properties of Cu(In,Ga)Se2 grown by close-spaced vapor transport technique

Polycrystalline thin films CuGa0.3In0.7Se2 (CIGS) were deposited onto coated soda-lime glass and transparent conducting oxide (SnO2) substrates at 480 °C substrate temperature with a low cost and potentially large area deposition method by using close-spaced vapor transport technique (CSVT) designed in our laboratory (LAMPS). Morphological, structural and compositional properties were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. Optical transmission spectra were used to determine absorption coefficient and gap energy of the sample. Using photoacoustic spectroscopy, we report the activation energies of shallow and deep levels. Finally, we discuss the results obtained.