Radiation defects in thin films of Cu(In, Ga)Se₂ solid solutions irradiated by hydrogen ions

The quality crystalline structure and phase composition of Cu(In, Ga)Se₂ (CIGSe) thin films fabricated on Mo-coated glass substrates were analyzed by X-ray diffraction. The unit cell parameters of CIGSe solid solutions were determined using the approximation of experimental shape of diffraction peaks by a Pseudo-Voigt function and Rietveld refinement method. The optical properties of CIGSe thin films implanted with 2.5 – 10 keV hydrogen ions to fluencies ranging from 10¹⁴ to 10¹⁷ cm^-2 were studied using the low-temperature (~4.2 K) photoluminescence (PL) spectroscopy. It was found that the implantation of H⁺ ions generated two or three optical bands in the PL spectra. The origin of these PL bands was attributed to intrinsic defects caused by implantation H⁺ ions in CIGSe thin films. (authors)