Agitation dependent properties of copper indium diselenide thin films prepared by electrochemical route

• The open circuit potential depends on the agitation conditions of the bath.
• Agitation conditions and growth potential strongly influence the surface morphology.
• Highly polycrystalline and stoichiometric CIS layers are deposited at − 0.6 V without agitation.

CuInSe2 (CIS) thin films have been prepared by potentiostatic electrochemical synthesis route in an aqueous medium. A conventional three-electrode electrochemical geometry was used to study the influence of agitation on electrodeposition of CIS. The co-deposition potentials for Cu-In-Se, − 0.4 V and − 0.6 V were optimized by using cyclic voltammetry measurements. The diffusive controlled growth with instantaneous nucleation is observed by Chronoamperometric measurements. X-ray diffraction (XRD) and Raman spectroscopy, UV–Vis spectroscopy, energy dispersive X-ray analysis (EDAX) and scanning electron microscopy (SEM) were employed to study the structural, optical, compositional and morphological properties, respectively. Polycrystalline CIS thin films with tetragonal structure were obtained without agitation, however the secondary phases of CuxSey were attributed with agitation. The Raman results are found to be in good agreement with XRD and EDAX analyses. Without agitation the energy band gap (Eg) was estimated ~ 1.1 eV. The higher values of Eg ~ 1.5 to 1.8 eV measured for the samples grown with agitation are proposed due to the inhomogeneous growth of precursors and the change in surface morphology. Uniform, compact and well adherent CIS layers were deposited with and without agitation. The deposition potentials and agitation conditions were found to be greatly affected on the surface morphology. The stoichiometric CIS layer was deposited at − 0.6 V without agitation.