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Based on an n-type Czochralski silicon textured absorber, SANYO Ltd. has developed a silicon heterojunction solar cell called heterojunction with intrinsic thin layer (HIT) with an efficiency over 20% . Fabrication of HIT involves depositing thin hydrogenated amorphous silicon (a-Si:H) layers on both sides of a high-quality crystalline silicon (c-Si) wafer by plasma-enhanced chemical vapour deposition. This process can realize excellent surface passivation and p–n junction formation simultaneously. The low processing temperature (o200 1C) prevents the bulk property degradation of the substrate that is usually observed in high-temperature processes. Further, compared with the conventional diffused solar cells, HIT solar cells have a better temperature coefficient and a higher open-circuit voltage (VOC) [2–4]. For these reasons, HIT solar cells have been extensively investigated. Although SANYO’s original design used an n-type substrate as the absorber for the HIT solar cell, current researches concentrate on developing the HIT solar cell on a p-type substrate, because of its popularity in the photovoltaic industry [5–7]. However, inferior performance was observed for devices fabricated on c-Si(p) as compared with those on c-Si(n). This was once attributed to the poor back surface field (BSF) effect at the c-Si(p)/a-Si:H(p+) interface due to the large valence band offset there [8,9]. Recently, NREL obtained a decent HIT performance on c-Si(p) utilizing the a-Si:H(p+) BSF , which suggests that a further investigation is necessary to fully understand the factors that affect the performance of the c-Si(p)-based HIT solar cell, although such work has been carried out to some extent [11,12].