Atomic Layer Deposited Al1−xNixO: Low Contact Resistivity Hole‐Selective Contact for Crystalline Silicon Solar Cells

Transition metal oxide (TMO)/crystalline silicon (c‐Si) junction‐based heterostructure crystalline silicon solar cells have emerged as a promising alternative to traditional silicon solar cells. However, the power conversion efficiency of c‐Si solar cells utilizing a nickel oxide (NiO x ) hole transport layer (HTL) still lags behind those employing a fully developed TMO layer. This disparity may be attributed, at least in part, to inefficient hole extraction. Atomic layer deposited (ALD) aluminum nickel oxide (Al 1 − x Ni x O) films, synthesized using bis( N,N′‐di‐t ‐butylacetamidinato)nickel(II) (NiAMD) and trimethylaluminum (TMA) as precursors, along with deionized water as a co‐reactant, have been observed to improve the contact properties with p‐type silicon compared to NiO x . Al 1− x Ni x O films with varying Al concentrations (0.25, 0.44, and 0.87) are examined for their contact performance on p ‐Si, resulting in the lowest contact resistivity of 85 mΩ cm 2 . Optimized Al 1 − x Ni x O films exhibit superior hole extraction capability from p‐type silicon, leading to a remarkable conversion efficiency of 19.35% in the constructed p ‐Si/Al 1 − x Ni x O/Ag solar cell. These findings underscore the advantages of utilizing ALD Al 1 − x Ni x O as a hole‐selective contact for crystalline p ‐Si solar cells.