Effects of contact electrode size on the characteristics of polycrystalline-Si p-i-n solar cells

The effects of contact electrode size on the photo-voltaic characteristics of polycrystalline-Si p-i-n solar cells have been studied,with respect to a unit-cell pitch size of 1 μm width.For the non-transparent A1 contact electrode with a contact width of 0.05-0.2 μm,the short-circuit current is obviously reduced with increasing contact width,due to a larger area of optical reflection by the electrode.On the other hand,even when using a transparent ITO (indium-tin-oxide) electrode,a larger width of contact electrode may also cause a smaller short-circuit current,due to a larger area of optical absorption by the electrode.However,for this ITO electrode,the contact electrode of 0.05 μm width causes a smaller short-circuit current than that of 0.1 μm width,primarily ascribed to a smaller area for collecting carrier and a larger contact resistance.As a result,while using the ITO contact electrode to enhance the conversion efficiency of the solar cell,a proper width of contact electrode should be employed to optimize the photo-voltaic characteristics.