Chemical bath deposition (CBD) technique is very attractive, since it is relatively simple, economic and convenient to grow nanostructured chalcogenide thin films at room temperature. In this paper the effect of Fe ion source, Fe (NO3)3.9H20 on optical properties of FeSe thin films is discussed.The as deposited FeSe thin films are polycrystalline in nature with tetragonal lattice. The optical absorption measurements show that the optical band gap energy of FeSe changes from 2.67 to 2.60 eV depending on Fe ion concentration in deposition bath.
