Comparative Study of the Effect of the Hubbard Coefficient U on the Properties of TiO2 and ZnO

•In TiO2, as the U factor increases, both the BG and the unit cell parameters increase.•For ZnO, as U increases, BG increases but the structure parameters decrease.•The BG value reaches a maximum from which it decreases in the case of titania.•An increasing and linear behavior is observed for the BG width on ZnO.•The effects of Ud parameter are especially visible in CB for TiO2 and in VB for ZnO.