Preparation and characterization of electrodeposited Bi2Se3 thin films

Thin films of Bi2Se3 have been prepared from an aqueous acidic bath at room temperature using selenium dioxide as a selenium ion source by a simple, inexpensive electrodeposition technique. The electrodeposition potentials for different bath compositions and concentrations are estimated from polarization curves. It has been found that Bi(NO3)(3) and SeO2 in the volumetric proportion as 7:3 and their equimolar solutions of 0.025 M form good quality films. The films are annealed in a nitrogen atmosphere at 200 degrees C for 2 h. The films are characterized by scanning electron microscopy, X-ray diffraction and optical absorption techniques. Studies reveal that as-deposited and annealed thin films are continuous and polycrystalline in nature. The optical band gap has been found to be 0.55 eV for the above-mentioned composition and concentration of the film. (C) 1998 Elsevier Science S.A. All rights reserved.