Impact of substrate type on the surface and properties of electrodeposited Cu2O nanostructure films as an absorber layer for solar cell applications

Abstract

Low cost electrodeposition method was employed to grow Cu2O nanostructure thin films on different conductive substrates (Au, ITO, and FTO). Here for first time, influence of substrate on morphology, structural, and optical properties of electrodeposited thin films as active layer for solar cell applications were investigated employing scanning electron microscopy, X-ray diffraction, Uv–vis spectroscopy, and photoluminescence. The results indicate single-phase formation of polycrystalline cubic structure of Cu2O thin film on the three substrates. Only the (111) diffraction plane was appeared on ITO and Au substrates demonstrating a good crystal quality. The formed Cu2O on Au substrate have the smallest grain sizes and highest surface area. Optical results show that the fabricated Cu2O films have band gap of 2.03, 2.03 and 1.93 eV for Au, ITO, and FTO substrates respectively. The grown Cu2O crystals on Au substrate have the lowest PL intensity that indicate the higher performance to separate the photogenerated carriers and lowest recombination rate as well as high crystal quality. I–V characteristic curves of the fabricated thin films showed that samples have a non-linear rectification behavior while Cu2O deposited on Au substrate has the highest forward current. I–V results confirmed and supported all the other obtained results from XRD, SEM, and PL techniques. Therefore, the results designate that the electrodeposited Cu2O thin film on Au substrate is the most favorable for solar cell applications.