Influence of X-ray irradiation on the optical absorption edge and refractive index dispersion in Cu6PS5I-based thin films deposited using magnetron sputtering - I. P. Studenyak; M. M. Kutsyk; A. V. Bendak; Yu. Izai; P. Kúš; M. Mikula (Semiconductor Physics, Quantum Electronics and Optoelectronics, 2017)