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

Abstract

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 (NiOx) 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 (Al1−xNixO) 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 NiOx. Al1−xNixO 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 cm2. Optimized Al1−xNixO films exhibit superior hole extraction capability from p‐type silicon, leading to a remarkable conversion efficiency of 19.35% in the constructed p‐Si/Al1−xNixO/Ag solar cell. These findings underscore the advantages of utilizing ALD Al1−xNixO as a hole‐selective contact for crystalline p‐Si solar cells.