Enhanced optoelectronic properties of Mg doped Cu₂O thin films prepared by nebulizer pyrolysis technique

In the present work, pure and magnesium doped Cu₂O films were deposited on glass substrates by nebulizer spray pyrolysis method with doping concentrations of 0, 3, 5 and 7% at 280 °C. The as-prepared films were analyzed by XRD, AFM, laser Raman, UV–Vis, photoluminescence, Hall Effect measurements. An X-ray diffraction study clearly depicts that films are possessing polycrystalline nature with a cubic structure. The surface topological properties have been characterized using atomic force microscopy (AFM) which reveals nano shaped hill rock grains covered the surface of the substrate. Laser Raman spectroscopy studies confirm the peaks observed at 109, 148, 217, 416 and 514 cm⁻¹ belong to Cu₂O phase. UV–Vis spectrophotometer measurements show that the band gap is decreased from 2.25 to 1.9 eV for the increase of doping concentration Mg. Photoluminescence spectral analysis giving an emission peak at 630 nm confirmed the formation of cuprous oxide. The electrical studies showed that the films are of p-type. For the doping of 7% Mg concentration the Cu₂O showed a resistivity 1.53 × 10² andhigh carrier concentration of 21.67 × 10¹⁶ cm⁻³. FTO/ZnO/Cu₂O/Ag heterojunction was fabricated using 7% Mg doped Cu₂O thin film, and found the open circuit voltage (V_oc) as 0.25 V, short circuit current (I_sc) as 0.225 × 10⁻⁴ A and the efficiency as 0.65% for the 7% Mg doped Cu₂O thin film.