Yes it will, in some oxides there are several phases that may be formed during certain conditions which may be favoured in some synthetic methods compared with some others, this can have influence in the final material and its band gap properties

If a significant amount of dopants are introduced into the oxide during synthesis, it will create doping state, even doping band in the gap, which usually reduced the band gap of oxide. 

thanks a lot

yes ya mon frere. the bandgap is very dependent on particle size and especially at the nano scale where the quantum confinement occurs. kech DRX?