Neodymium oxide electron-selective contact for crystalline silicon solar cells

Wide-bandgap metal compound-based passivating contacts are expected to alleviate the recombination losses at the contact regions of crystalline silicon (c-Si) solar cells. In this work, we develop neodymium oxide (Nd2O3-x) electron-selective contact using thermal evaporation (TE) and atomic layer deposition (ALD). The elemental composition, work function (WF), surface passivation and contact performance of Nd2O3-x films, as well as their implementation on c-Si solar cells were investigated. The results indicate that both TE and ALD Nd2O3-x can effectively serve as electron-selective contacts for c-Si solar cells due to their low WF, and low contact resistivities of 4.8 mS2 cm2 and 33.1 mS2 cm2 on n-type c-Si are obtained, respectively. Proof-of-concept c-Si solar cells featuring a full-area ALD Nd2O3-x electron-selective rear contact achieve an efficiency of 21.3 %. This work provides new insights into the potential of wide-bandgap metal compound-based passivating contact for c-Si solar cells.