Development of Phosphorus-Doped Nanoscale Poly-Si Passivating Contacts via Inkjet Printing for Application in Silicon Solar Cells

Herein, high-quality localized phosphorus-doped polycrystal-line silicon (poly-Si) passivating contacts containing nanoscale poly-Si film (similar to 100 nm) on an ultrathin SiOx layer (similar to 1.5 nm) were fabricated via an inkjet printing technique. A detailed study of the impacts of inkjet printer settings, dopant concentration, and annealing temperature on the poly-Si passivating contact performance (represented by implied open-circuit voltage iVoc and contact resistivity rho c) was carried out. By applying optimized process conditions on symmetrical industrially processed intrinsic poly-Si/SiOx/n-type crystalline Si (c-Si) substrates, good surface passivation was achieved with an iVoc of 699 mV, together with a low rho c of 6.4 m omega center dot cm2, after annealing at 975 degrees C. After a hydrogenation treatment via the deposition of aluminum oxide (AlOx)/silicon nitride (SiNy) stack and subsequent forming gas annealing (FGA), the optimum annealing temperature shifted to 950 degrees C and the iVoc was further improved to an excellent value of 729 mV. Optical images reveal that a line width of 75 mu m can be realized on a mechanically polished silicon wafer. Moreover, high-resolution micro-photoluminescence (mu-PL) maps clearly demonstrate the localization of the doped regions on the symmetrical substrate after annealing. These results show that inkjet printing is a promising technique for the fabrication of localized poly-Si/SiOx passivating contacts in high-efficiency solar cells with high flexibility and simplicity.

Automated summary

In this study, high-quality localized phosphorus-doped polycrystalline silicon passivating contacts with nanoscale poly-Si film on an ultrathin SiOx layer were fabricated using an inkjet printing technique. The effects of printer settings, dopant concentration, and annealing temperature on the contact performance were investigated. Good surface passivation was achieved with optimized conditions, and after hydrogenation treatment, the implied open-circuit voltage was further improved.