Enhanced open-circuit voltage in p-type passivated emitter and rear cell by doped polysilicon layer as passivation contact. (1st September 2020)

• Record Type: Journal Article
• Authors: Xu, Yajun; Shen, Honglie; Yang, Zhi; Wei, Qingzhu; Ni, Zhichun; Li, Shubing; Wang, Zehui; Zhao, Baoxing
• Is Part Of: Solar energy. Volume 207(2020)
• Page Start: 436
• Page End: 440
• Publication Date: 2020-09-01
• Subjects: Passivation contact -- Polysilicon -- Carrier-selective -- PERC cell; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2020.07.002
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Doped poly-Si/SiOx passivation was used for front side of p-type PERC cell. Obvious passivation effect was obtained in the PERC cells with the poly-Si/SiOx . Dark recombination current density was reduced to about 3 fA/cm 2 in test sample. An enhanced Voc value of 10 mV was achieved in the passivated p-type PERC cell. Abstract: The most promising and feasible approach to achieving high-efficiency silicon solar cells must be passivation contact compatible with current homojunction thermal processes. In this paper, an easy-to-implement carrier-selective passivation contact with doped poly-Si/SiOx for produing p-type passivated emitter and rear cell (PERC) was proposed. The passivation contact structure consisted of an ultra-thin SiOx layer capped with an intrinsic amorphous silicon (a-Si) layer prepared by low pressure chemical vapor deposition, which was deposited onto a p-type silicon substrate and then was doped and re-crystallized by a thermal phosphorus diffusion at 850 °C for 75 min. By optimizing the diffusion profile and cleaning time, a low dark recombination current density J0 ≈ 3 fA/cm 2 and large minority carrier lifetime of 3000 μs were achieved on the 180-μm-thick n-type wafers with a resistivity of 3 Ω·cm, corresponding to an implied open-circuit voltage of 700 mV. P-type PERC cells with the highly doped poly-Si/SiOx passivated emitter demonstrated 683.97 mV of open-circuit voltage, showing more than 10 mV enhancement comparing with regular PERC cells. The results demonstrated an attractive potential of the carrier-selective passivation contacts with doped poly-Si/SiOx under front metallizatin area in photovoltaic application.