V oc saturation effect in high-temperature hydrogenated polycrystalline silicon thin-film solar cells

Abstract

Hydrogenation of polycrystalline silicon thin-film solar cells is performed to improve the one-sun open-circuit voltage (V oc) of the device. V oc is found to increase linearly with increasing hydrogenation temperature and then saturates. For planar and textured samples, the V oc saturates at about 340°C and 307°C respectively. The low hydrogenation temperature helps to lower thermal budget during industrial process. Arrhenius plot of V oc prior to the saturation shows that the textured samples have lower activation energies than the planar sample. The activation energies of samples 188 (planar), 788 (textured) and 888 (textured) are 1.31 eV, 0.86 eV and 0.92 eV, respectively. The lower activation energies of the textured samples could be due to the shorter diffusion thickness and the increased surface area that is exposed to the hydrogen plasma. © 2011 Materials Research Society.