Thermal annealing of flash evaporated Cu(In, Ga)Se2 thin films

Abstract The electro-optical properties of semiconductors including Cu(In, Ga)Se 2 compounds suffer from various types of intrinsic defect levels such as grain boundaries and dislocations. The type and number of these can vary considerably, depending on the various aspects of the fabrication processes of the semiconductors. However, the properties of the material can be improved significantly by employing post-deposition procedures. This paper presents results of studies carried out on the post-deposition thermal annealing of flash evaporated thin films of Cu(In, Ga)Se 2 . The structural and electro-optical properties were analyzed using a variety of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford backscattering (RBS). A high resolution near-infrared photoacoustic spectrometer has also been employed to assess improvements in the optical properties following thermal annealing and correlated with the crystallite structure. Results obtained for thin films of CIGS were compared to data gained from studies carried out on single crystals.