This work was devoted to studying the atomic structure and electron spectrum of a-SiOx : H films created on silicon and glass substrates by means of plasma-enhanced chemical vapor deposition (PECVD). Depending on the conditions of oxygen supply into the reactor, the stoichiometric parameter x of the films was varied from 0.57 to 2. The structure of the films and the specific features of their electron structure were characterized depending on the parameter x with a complex of structural and optical methods and ab initio quantum-chemical simulation for the model SiOx structure. The studied SiOx : H films were established to consist predominantly of silicon suboxides SiOy, SiO2 clusters, and amorphous silicon. Based on the spatial fluctuations of their chemical composition, the model of bandgap width and potential fluctuations was proposed for SiOx electrons and holes. The obtained data would provide the charge transport in a-SiOx : H films with more precise modeling important for the creation of nonvolatile random-access memory (RAM) elements and memristors on their basis.