Electrochemically modified crystal orientation, surface morphology and optical properties using CTAB on Cu2O thin films

Cuprous oxide (Cu2O) thin films with different crystal orientations were electrochemically deposited in the presence of various molar concentrations of cetyl trimethyl ammonium bromide (CTAB) on fluorine doped tin oxide (FTO) glass substrate using standard three electrodes system. X-ray diffraction (XRD) studies reveal cubic structure of Cu2O with (1 1 1) plane orientation, after addition of CTAB in deposition solution, the orientation of crystal changes from (1 1 1) into (2 0 0) plane. Scanning electron microscope (SEM) images explored significant variation on morphology of Cu2O thin films deposited with addition of CTAB compared to without addition of CTAB. Photoluminescence (PL) spectra illustrate that the emission peak around at 650 nm is attributed to near band edge emission, and the film prepared at the 3 mM of CTAB exhibits much higher intensity than that of the all other films. UV-Visible spectra show optical absorption in the range of 480-610 nm and the highest transparency of Cu2O film prepared at the concentration of 3 mM CTAB. The optical band gap is increased in the range between 2.16 and 2.45 eV with increasing the CTAB concentrations.