Atomic layer deposited NiOxAly and ZnxNiyO as hole selective contacts for silicon solar cells
Tian Zhang1, Md. Anower Hossain1, Kean Khoo1, Chang-Yeh Lee1, Yahya Zakaria2, Amir A Abdallah2, Bram Hoex2
1School of Photovoltaic and Renewable Energy Engineering, UNSW , Sydney, Australia
/2Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Doha, Qatar

Atomic layer deposited NiOxAly and ZnxNiyO films with different concentrations are investigated as hole selective contact for crystalline silicon solar cells. Spectroscopic ellipsometry revealed that the ZnxNiyO films have a bandgap of > 3 eV. The incorporation of Zn or Al in NiO significantly decreases the contact resistivity and thus improves the hole selectivity of the film. These results are consistent with density functional theory calculations which show that the Zn contributed extra electronic states and Al introduced shallow defects in the bandgap can facilitate the hole transport. This work demonstrates the potential of NiOxAly and ZnxNiyO as hole-selective contacts for crystalline solar cells.