A transparent hole-selective passivating contact for crystalline silicon solar cells: niobium-titanium oxide formed by atomic layer deposition

Abstract We propose a niobium titanium oxide/silicon oxide (SiO y ) stacked structure as a hole-selective passivating contact for crystalline-silicon solar cells. This structure showed passivation quality and electrical properties comparable to those of conventional passivating contacts based on hydrogenated amorphous silicon, while simultaneously exhibiting lower parasitic absorption and higher tolerance to sputtering processes of transparent conducting oxides. Thermal desorption spectroscopy revealed that a considerable number of Si–OH bonds was formed in this structure, accounting for the good passivation. These findings represent a significant step toward improving crystalline-silicon solar cells using passivation layers composed purely of oxides.