Improving the conductivity of cuprous oxide thin film by doping Calcium via feasible nebulizer spray technique for solar cell (FTO/ZnO/Ca-Cu₂O)

Calcium-doped cuprous oxide (Ca:Cu₂O) thin filmswere effectively coated onto glass substrate by nebulizer spray techniquewith different doping percentage (0%, 1%,2%and 3%).X-ray beam diffraction confirms the polycrystalline nature of the prepared Cu₂Othinfilm.An increase in size of the crystallites from11 nmto 29nmwas observed for the increase of doping concentration.AFMstudy exposed a smooth surfacewith evenly dispersed grains and the change in roughness on the filmsurface was also noticed.Opticalmeasurements showed the band gap varied from2.40 eV to 2.15 eV for undoped and doped films.All the filmswerewith narrowemissions band at 630 nmfor excitation at 450 nmfromthe PL spectra.Hall Effectmeasurements showed that the prepared films have p-type conducting nature with resistivity value of 0.453 × 10²Ωcm and the carrier density of 21 × 10¹⁹ cm^-3 for the3%Ca-doping concentration. Solar cell characteristics such as an open circuit voltage (V_oc) of 0.30mV, fill factor (FF) of 0.33 and conversion efficiency (n) of 0.45%were attained for 3%Ca doped Cu₂Ofilm.