Fabrication of Electrodeposited SnS/SnO₂ Heterojunction Solar Cells

SnO₂ thin films were successfully electrodeposited from an aqueous oxygen-bubbled tin sulfate solution and partnered with electrodeposited SnS thin films to fabricate SnS/SnO₂ heterojunction solar cell. The electrodeposited SnS/SnO₂ superstrate structure with 250-°C-annealed SnO₂ as a window layer exhibited an open circuit voltage of 40–90 mV and a short circuit current density of 1.5–9.7 mA/cm². The solar conversion efficiency was estimated to be in the order of 10^-2–10^-1%. The band discontinuities at the SnS/SnO₂ interface were evaluated by X-ray photoelectron spectroscopy. The valence band offset was determined to be approximately 1.85 eV. Using this value and the band gaps of individual layers, the conduction band minimum of SnO₂ is predicted to be higher than that of SnS by 0.65 eV.