In this article, we consider defect formation in hafnium oxide, which belongs to high-K dielectrics and is a promising material in different areas of nano- and optoelectronics. Hafnium oxide, synthesized by the method of atomic layer deposition, usually forms with a significant oxygen deficiency and contains large number of vacancies. The oxygen vacancies characterized by photoluminescence methods. We showed that the electron-phonon interaction greatly influenced on formation of emission bands. In this case, the emission band can’t identify only by the emission maximum. We need to calculate such band parameters as heat release and the energy of a purely electronic transition. This energy that can be compared with the results of theoretical calculations from the first principles.