The nanocrystalline Bi2O3 powder was synthesized by ultrasonicated microwave irradiation by employing centrifugation technique at all
normal conditions. Fabrication of thick films of pure Bi2O3 powder was made by screen printing and firing at 400oC for 30 min. Surface
activations of the films involved the dipping of pure films into 0.01M aqueous solution of Gallium Nitrate for different intervals of time. The
morphologies, surface topographies, constituents of elements present in the synthesized materials and crystallographic structures of the pure
and surface activated films have been investigated by XRD, FE-SEM, E-DAX, etc. It has been investigated that, the Ga2O3 activated Bi2O3
(30 min) sample exhibits crucial response to 20 ppm Cl2 gas at 250oC. Electrical and gas monitoring performance of thick films of pure and
activated Bi2O3 have been studied and discussed.