Implementation of ALD-grown MgO layers as electron-selective contact for silicon solar cells

Abstract

This work focuses on the investigation of Magnesium oxide (MgO) layers as passivating electron selective contact for silicon solar cells. It was observed that MgO layers produced by atomic layer deposition (ALD) do not provide good passivation by themselves on c-Si wafers. Therefore, an intermediate passivation layer was needed to maintain a high VOC in solar cells with MgO layers. In this work, i-aSi:H layers were considered as a passivating buffer layer. The low MgO deposition temperatures (< 200°C) ensured compatibility with i-aSi:H layers. We investigate the dependence of solar cell performance on MgO layer thickness and influence of the annealing on the device performance. Additionally, possible metallization schemes at the interface to the MgO layer are discussed.