Silicon Photovoltaic Cells with Deep p–n-Junction

Abstract

By the diffusion obtained the Si 〈B, P〉 (group I) and Si 〈B, P + Ni〉 (group II) structures with deep p–n-junctions. It is demonstrated that the parameters of silicon photovoltaic cells with deep p–n-junctions are improved due to nickel doping. After nickel diffusion, the average value of the open circuit voltage Voc of the photo cells to group I increases by 19.7%, and the short-circuit current density Jsc in-creases by 89%. It was established that the formation of nickel clusters occurs at the optimum temperature of thermal annealing T = 750–800°C. The relative increase in the efficiency of photovoltaic cells after ad-ditional thermal annealing at T = 800°C is 118.8%. In addition, in samples with a nickel-enriched area on the front side of the p–n-junction, the fill factor of the current–voltage characteristic increased by 30%. The influence of nickel atom clusters on the bulk properties of the base and the properties of the surface regions of the solar cell, where the concentration of nickel atoms is 2–2.5 orders of magnitude greater than in volume, is considered. It is proved that the nickel-rich n-layer near-surface region plays a significant role in increasing the efficiency of photovoltaic cells. Experimental results show that an increase in the lifetime of minority charge carriers leads to a sig-nificant increase in the solar cell collection factor. We associate the obtained data mainly with the getter properties of nickel atom clusters. We assume that doping with nickel clusters can increase the absorption coefficient of the base of the solar cell in the infrared region of the spectrum due to the appearance of plasmon resonance, which should lead to a better alignment of the absorption region of infrared light with the p–n-junction.