Solar cells on foreign substrates using poly-Si thin films by metal induced growth

The poly-Si film was deposited by using the metal-induced growth (MIG) method on tungsten substrates. By making Au/n-Si Schottky photo-diodes, doping density effect was studied by using three different doping level Si sputtering targets. Increasing the Si target resistivities from 0.02Ω-cm to 50Ω-cm, open-circuit-voltage (V_oc) decreased from 0.22V to 0.14V while short-circuit-current density (J_sc) increased from 1.55mA/cm² to 2.42mA/cm². C-V results revealed a high charge density in the device, which may be due to the oxygen thermal donor effects. Using an oxygen filter for the sputtering gas effectively reduced the charge densities and increased the J_sc value. The p/n junction solar cells were fabricated by using ion implantation at 10¹³-10 ¹⁴cm^-2 dose and 100-200keV. The cells with wider emitter layer by double-ion implantation gave higher J_sc and V_oc values. Passivation of the Si film by using hydrogenation improved the J _sc, V_oc and spectral response of the solar cells.