Atomic Layer Deposited AlxNiyO as Hole Selective Contact for Silicon Solar Cells

Atomic layer deposited Al _x Ni _y O with different concentrations of Al are investigated as hole selective contact for crystalline silicon solar cells. Spectroscopic ellipsometry reveals that these Al _x Ni _y O films have a bandgap of 2.8-3.3 eV. This incorporation of Al increases the hole selectivity of the NiO film in a way that the contact resistivity of the Al _x Ni _y O films with Si is significantly lower. These results are consistent with density functional theory calculations indicating the presence of shallow defects in the bandgap of Al _x Ni _y O which contribute to the improved hole selectivity. This work demonstrates the potential of Al _x Ni _y O as a hole-selective contact for crystalline solar cells.