Physical properties of Cu2O thin films prepared with different thicknesses of the annealing temperature effect on

In this thesis, semiconductor Cu2O thin films are obtained using SILAR (Succesive Ionic Layer Adsorption and Reaction) method at 70 °C on a substrate through 10, 30 and 40 immersion cycles. The films then are subjected to different annealing procedures at 100, 300 and 500 °C. The effect of various annealing temperatures are examined in terms of the change in structural, optical, morpholgical and electrical properties of the films. The XRD analyses indicate that Cu2O thin films exhibit a polycrystal structure and cubic phase. It is also concluded that annealing leads to a transition from Cu2O to CuO in the thin film structure. Optical parameters such as energy band gap (Eg), reflectivity (R) and refractive index values are acquired using aforementioned basic parameters. Optical transmittance values of Cu2O thin films in the visible region are attained to be between 2-61% whereas calculations for refractive indices (n) indicate that the values vary between 2.14-11. There found to be an inverse correlation between the annealing temperature and energy band gap values (Eg) where an increase in the anneling temperature leads to a drop in the energy band gap of given thin films within the interval of 2.57-1.77 eV. FE-SEM (Field Emission Scanning Electron Microscope) analyses demonstrate that a homogeneous spherical structure through the sample is observed. A more closely-packed structure is detected with respect to increasing annealing temperature. From the Hall effect measurement, it was found that Cu2O and CuO thin film exhibits p-type conduction. The resistivity values of Cu2O and CuO thin films are measured to be 7.4x103-1.1x104 ve 5.1x102-8.2x103 Ωcm, respectively.