Metallized Boron-Doped Black Silicon Emitters For Front Contact Solar Cells

We study doping and metallization of black silicon (bSi) boron emitters formed by ion implantation or diffusion. We demonstrate that conformal metal layers can be deposited on bSi by electron beam evaporation. Raman spectroscopy shows that high boron concentrations (4·10 ¹⁹ cm ^-3 ) are obtained in bSi by ion implantation, while maintaining emitter saturation current (J _0e ) below 20 fA/cm ² with Al ₂ O ₃ passivation. In diffused bSi emitters, doping increases to twice the values of planar substrates, reaching values up to 7·1020 cm ^-3 . Those doping values allow specific contact resistivities down to (0.3 ± 0.2) mΩ·cm ² on boron-implanted bSi surfaces with nickel or aluminum contacts.