In this work the effect of substrate type on structural properties of the Nb2O5 thin films deposited on silicon and quartz substrate by spin coating technique is present. The formation of Nb2O5 thin films having an obvious polymorphous monocline structure. A significant enhanced was observed on the crystalline structure of films prepared on the silicon substrate, were more distinguished peaks comparing with quartz substrate was appeared. The structural the estimated structural constants reveal an increase in the estimated grain size of the prepared films on the silicon substrate. The lattice stress of the deposited films on Quartz and silicon was 0.19 and 0.15 respectively. Effect of number of deposited layers are also studied showing an increase in the absorbance, extinction coefficient (k), refractive index (n), optical conductivity, real (εr) and imaginary (εi) dielectric constant and decreasing in the band gap from (2.69) to (2.51) e.v as a result of increasing in the film number of layers from (3) to (6) layers.
