Comprehensive growth and characterization study of GeOx/Si

•The effect of thickness on the structural and optical properties of GeO2 films have been investigated by experimental.•The intensity of (113) is the highest in the spectrum of 240.22 nm thickness.•As the thickness increases, the energy band gap increases from 4.1 eV to 4.4 eV.•The refractive index increases as the thickness increases.•The increase in Ed as the thickness of the films increases is related to the increase in the lattice parameters.