Pulse Electrodeposition of CuO Thin Films to Improve Crystallinity for the Enhancement of Photoelectrochemical Response

Pulse electrodeposition of p-type CuO semiconductor films for the light absorption layer of photovoltaic cells was conducted. Shapes of the potential pulse affected the crystallinity of CuO films. X-ray diffraction (XRD) spectra of all the CuO films among this study showed (002) orientation through the heteroepitaxial growth on the (111)-oriented Au substrates. The CuO layer formed with the most favorable pulse condition showed a sharp diffraction peak assigned to (002) plane of CuO with 0.20° of full width at half maximum (FWHM) value, in contrast to that of the CuO film potentiostatically deposited at 850 mV vs. Ag/AgCl being 0.46°. The FWHM values indicated that the pulse-deposited CuO film had much better crystallinity and contained less residual stress induced by electrodeposition than the potentiostatically deposited CuO. Photocurrent of the pulse-deposited CuO film in NaOH solution was greater than that of the potentiostatically deposited CuO. This enhancement in photoresponse was considered to be due to the high crystallinity of pulse-deposited CuO.