Improved cleaning process for post-texture surface contamination removal for single heterojunction solar cells on ∼25µm thick exfoliated and flexible mono-crystalline silicon substrates

An improved cleaning process is developed to remove surface contamination before depositing amorphous silicon on a textured surfaces of ~25μm thick exfoliated and flexible monocrystalline substrates. Auger electron spectroscopy is used to monitor the change in atomic percentage on the surface to reflect the effect on contamination removal due to different cleaning processes. Quantitative analysis of the spectra shows significant reduction (~0.9% atomic) in key contaminant i.e. potassium with the newest cleaning procedure. Electrical data is collected on completed single heterojunction cells on exfoliated substrates to compare between the old process and the new improved process for cleaning the textured surface. An overall enhancement of 22mV and an absolute increase of 1.5% in conversion efficiency are observed with the new and improved cleaning procedure.