Light-induced degradation of PECVD aluminium oxide passivated silicon solar cells

Abstract

Light-induced degradation (LID) has been identified to be a critical issue for solar cells processed on boron-doped silicon substrates. Typically, Czochralski-grown silicon (Cz-Si) has been reported to suffer from stronger LID than block-cast multicrystalline silicon (mc-Si) due to higher oxygen concentrations. This work investigates LID under conditions practically relevant under module operation on different cell types. It is shown that aluminium oxide (AlOx) passivated mc-Si solar cells degrade more than a reference aluminium back surface field mc-Si cell and, remarkably, an AlOx passivated Cz-Si solar cell. The defect which is activated by illumination is shown to be doubtful a sole bulk effect while the AlOx passivation might play a certain role. This work may contribute to a re-evaluation of the suitability of boron-doped Cz- and mc-Si for solar cells with very high efficiencies

Lifetime degradation and regeneration in multicrystalline silicon under illumination at elevated temperature

“…5,6 The degradation was observed to a lesser extent on solar cells with a full-area aluminum back surface field (Al-BSF). Similar results were more recently reported by Fertig et al, 7,8 who described the degradation of mc-Si passivated emitter and rear cells (PERC) on even larger timescales at 0.15 suns and 70…”

Accelerated light-induced degradation for detecting copper contamination in p-type silicon

“…[31][32][33] Our results suggest that the partial recovery could be a fingerprint of copper contamination and the dark anneal could be used to determine whether the observed degradation is caused by copper.…”

Recombination activity of light-activated copper defects in p-type silicon studied by injection- and temperature-dependent lifetime spectroscopy

“…This phenomenon has been traditionally ascribed to the formation of metastable boron-oxygen (B-O) complexes, whose composition has been intensively debated in the literature. 1,2 However, recent results that showed severe LID in solar cells fabricated from multicrystalline silicon substrates 3,4 with low bulk oxygen content have raised numerous discussions on alternative defect reactions, which might explain the observed degradation process. Low levels of copper contamination have been recently shown to cause a similar LID effect in both mono- 5 and multi crystalline silicon.…”