Suppression of light degradation of carrier lifetimes in low-resistivity CZ–Si solar cells

Abstract

An international joint research has been conducted to investigate light degradation of low-resistivity Si CZ wafers and also to provide practical solutions to suppress the degradation. Ten kinds of CZ, MCZ and FZ Si wafers were evaluated under AM1.5 irradiation and processed to fabricate solar cells using low- and high-temperature processes. Lifetime degradation was suppressed using MCZ Si wafers with low oxygen content and Ga-doped CZ wafers with high oxygen content. In addition, high-temperature oxidation was also effective to reduce light degradation remarkably. No degradation of solar cells could be realized by using B-doped MCZ and Ga-doped CZ wafers combined with a high-temperature processing.