All-solution processed n-ZnO nanorods/i-CdS/p-Cu₂O diodes prepared using diluted solution precursors

N-ZnO nanorods/i-CdS/p-Cu₂O diode structures were prepared on ITO-coated soda lime glass substrates using an all-solution process. The ZnO nanorods and Cu₂O layers were synthesized by electrochemical deposition, and the intrinsic CdS layers were conformally coated by chemical bath deposition. The aqueous solution for the i-CdS coating was diluted to various pH values for the suppression of chemical etching of the underlying ZnO nanorods. The best p-i-n diode sample was produced from the i-CdS layer prepared with 15% CdSO₄ precursor (pH = 11), and it exhibited a distinct rectifying electrical performance with reduced leakage current because of the increased shunt resistance and the formation of a uniform i-CdS thin film.