Abstract

Junctions between transparent conductor (ITO) and single-crystal silicon or polycrystalline silicon (poly-Si) were prepared. Electrical I–V and C-V, as well as photovoltage decay (PVD) measurements, were performed. Data of open circuit voltage (V_oc), short circuit current (I_sc), fill factor (FF), efficiency (η), built-in potential (ϕ-_bl), and lifetime were obtained. It was found that the lifetime of photogenerated carriers in the poly-Si/ITO junction is much shorter than in single crystal. There are two types of recombination center that have an essential influence on the efficiency of the solar cells; those at the contact between ITO and the silicon; and those due to the grain boundaries (GB) between the crystallites in poly-Si. The solar cells were annealed, either by heating them in vacuum or by irradiation with the light of a Cd–Ne laser (441.6 nm). The annealing reduced the influence of the recombination centers at the contact, whereas those at the GB were not affected. Passivation of GB with iodine improved the characteristics of the solar cells. This improvement is attributed to the reduction of the recombination centers at GB. The influence of the annealing and passivation on the lifetime of this type of cell was studied by measuring PVD.

© 1985 Optical Society of America