Effect of structural, electrical and optical properties of electrodeposited bismuth selenide thin films in polyaniline aqueous medium

Thin films of Bi2Se3 and polyaniline (PAni)-doped Bi2Se3 films are prepared at three different concentrations by electrodeposition method. UV-vis absorption spectra of PAni-doped films show λmax at about 330 nm due to polyaniline. The optical band gap energy is found to be 2.35 eV for as-deposited Bi2Se3 thin film and it increases with increase in concentration of PAni. PAni-doped films show a shift in the FTIR peaks at 1281 cm-1 and 1069 cm-1. The X-ray diffraction measurements show that the intensity of doped films increases with increase in concentration of PAni. EDAX studies indicate that as-deposited films are nearly stoichiometric whereas doped films are off stoichiometric in nature. The morphology of the doped films changes due to the addition of PAni. The electrical conductivity measurements reveal that all the films follow Arrhenius behaviour. Activation energy varies from 0.025 eV to 0.096 eV for as-deposited film to doped films on increasing the concentration of PAni