Preparation and characterization of electrodeposited Bi2Se3 thin films from nonaqueous medium

Semiconducting Bi2Se3 thin films have been electrodeposited from nonaqueous medium at room temperature using selenium dioxide as a selenium ion source. The electrodeposition potentials for different bath compositions and concentrations of solution have been estimated from the polarization curves. It has been found that Bi(NO3)3·5H2O and SeO2 in various volumetric proportions varying from 9:1 to 1:9 with their equimolar solutions of 0.1 M form the Bi2Se3 films. The films are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and optical absorption techniques. The SEM studies show that the film covers total substrate surface with uneven surface morphology. The XRD patterns of the films show that the as-deposited films are polycrystalline with relatively more peak intensity at composition 9:1 and equimolar concentration 0.1 M. The optical band gap energy for direct transition in Bi2Se3 thin films is found to be 0.79 eV.