Influence of solution pH in electrodeposited iron diselenide thin films

摘要

Thin films of iron diselenide (FeSe_2) have been prepared on indium doped tin oxide coated conducting glass (ITO) substrates from an aqueous electrolytic bath containing FeSO_4 and SeO_2. Growth mechanism has been analyzed using cyclic voltammetry. The potential region in which the formation of FeSe_2 occurs is found to be -450 mV versus SCE. X-ray diffraction analysis showed that the deposited films are found to exhibit orthorhombic structure with preferential orientation along (12 0) plane. X-ray line profile analysis has been carried out to determine the microstructural parameters such as crystallite size, rms microstrain, dislocation density and stacking fault probability. Surface morphology and film composition have been analyzed using scanning electron microscopy, atomic force microscopy and energy dispersive analysis by X-rays, respectively. Optical parameters such as band gap, refractive index, extinction coefficient, real and imaginary dielectric constants, dielectric susceptibility and optical conductivity have been determined from optical absorption measurements. The observed results are discussed in detail.