Insights into the Si─H Bonding Configuration at the Amorphous/Crystalline Silicon Interface of Silicon Heterojunction Solar Cells by Raman and FTIR Spectroscopy

Abstract

In silicon heterojunction (SHJ) solar cell technology, thin layers of hydrogenated amorphous silicon (a‐Si:H) are applied as passivating contacts to the crystalline silicon (c‐Si) wafer. Thus, the properties of the a‐Si:H is crucial for the performance of the solar cells. One important property of a‐Si:H is its microstructure which can be characterized by the microstructure parameter R based on Si‐H bond stretching vibrations. A common method to determine R is Fourier transform infrared (FTIR) absorption measurement which, however, is difficult to perform on solar cells by various reasons like the use of textured Si wafers and the presence of conducting oxide contact layers. Here, we demonstrate that Raman spectroscopy is suitable to determine the microstructure of bulk a‐Si:H layers of 10 nm or less on textured c‐Si underneath indium tin oxide as conducting oxide. We perform a detailed comparison of FTIR and Raman spectra and find significant differences of the microstructure parameter obtained by both methods with decreasing a‐Si:H film thickness.This article is protected by copyright. All rights reserved