Understanding the Strong Apparent Injection Dependence of Carrier Lifetimes in Doped Polycrystalline Silicon Passivated Wafers

This study investigates the injection dependence of carrier lifetimes of p- and n-type samples passivated by doped-polycrystalline silicon (poly-Si) (p+ and n+ poly-Si) contacts. A strong apparent injection dependence of the carrier lifetimes is observed in p-n junction samples (p+ poly-Si on n-type or n+ poly-Si on p-type) but no injection dependence is observed in high-low junction samples (p+ poly-Si on p-type or n+ poly-Si on n-type). Further, photoluminescence images captured at two illumination intensities of 0.05 and 0.87 suns reveal that edge recombination contributed the strong apparent injection dependence in p-n junction samples. Furthermore, this apparent injection dependence increases as the sample size is reduced, and as the sheet resistance of the doped poly-Si contacts is decreased, allowing more effective transport of minority carriers to the recombination-active edge regions.The strong injection dependence of carrier lifetimes observed in p-n junction samples passivated by doped-poly-Si contacts increases as the sample size is reduced, and as the sheet resistance of the doped poly-Si contacts is decreased, allowing more effective transport of minority carriers to the recombination-active edge regions.image (c) 2024 WILEY-VCH GmbH