Spectroscopic ellipsometry investigation and morphological characterization of electrodeposited Cu₂O thin films: annealing effect

Abstract

The present paper demonstrates the annealing temperature effect on the structural, optical and morphological properties of electrodeposited copper (I) oxide (Cu2O) thin films on ITO-glass substrates. The optical properties were itemized by using spectroscopic ellipsometry (SE) and an adequate model was simulated using WinElli II software. The finite difference time domain simulation, X-ray diffraction and atomic force microscopy (AFM) data show good conformity with the SE measurements. For the surface roughness, good matching between the results of SE and AFM measurements was observed. The refractive index and extinction coefficient had decreased with increasing annealing temperature. On the contrary, the optical gap (Eg) had increased as the annealing temperature increases. Two optical band gaps observed in the sample annealed at 350°C indicate the presence of CuO and Cu2O phases. These results were confirmed by X-ray diffraction measurements.