Effect of solution molarity on structural and optical properties of nickel
hydroxide/ oxide films deposited by CBD
T. Taşköprü 1, 2*, E. Turan 1, M. Zor 1
1
2
Department of Physics, Anadolu University, Eskişehir 26470, Turkey
Department of Physics, Çankırı Karatekin University, Çankırı 18100, Turkey
Abstract
In this work, nickel hydroxide samples at different molarities (0.1M, 0.3M, and 0.5M) have been
successfully deposited using nickel nitrate as precursor in a mixed solution of ammonia onto glass
substrate by chemical bath deposition (CBD) method. The structural and optical properties of the
films have been investigated using XRD, SEM, and UV-Visible spectroscopy. XRD patterns show
that as-deposited films were β- Ni(OH)2 (Theophrastite, JCPDS 14-0117) have (001) preferred
orientation with 4.615Å interlayer spacing. Ni(OH)2 were annealed at 400°C for 1 h in air to obtain
NiO. The XRD results showed that all annealed films were polycrystalline in nature with face
centerd cubic structure (Bunsenite, JCSPD 47-1049) and preferred orientation along (111) plane.
The SEM images reveal that the surface morphologies of nickel hydroxide / oxide samples were
affected by the solution molarity. The deposited samples with 0.1 M is in the form of network
structured nanoflakes. The increase in molarity leads to change the nanoflake structure to nanosheet
formation. The absorbance and transmittance spectra of nickel hydroxide / oxide samples were
recorded by using Shimadzu Solid Spec 3700 UV-VIS-NIR Spectrophotometer in the wavelength
range of 200– 3300 nm in order to study the optical properties. The optical band gap of the NiO
films have been evaluated using Tauc’s equation. The band gap energy of NiO samples were found
to be in the range 3.72 and 3.80 eV depending on the solution molarity.