Modelling Heteroface of P.I.N Solar Cells for Improving Stability

Abstract

ABSTRACTThe introduction into a traditional p.i.n structure of two defective buffer layers near the p/i and i/n interfaces can improve the device stability and efficiency through an enhancement of the electric field profile at the interfaces and a reduction of the available recombination bulk centers. The defectous layer (“i'-layer”), grown at a higher power density, present a high density of defects and acts as “gettering centers” able to tailor light induced defects under degradation conditions. If the i-layer density of states remains below 1016 eV−1 cm−3 and assuming a Gaussian distribution of defect states, the gettering center distribution will not affect significantly the carrier population but only its spatial distribution.We report here about a device numerical simulation that allows us to analyse the influence of the “i'-layer” position, thickness and density of states on the a-Si:H solar cells performances. Results of some systematic simulation from the ASCA program (AMorphous Solar Cell Analysis), and for different configurations will be presented.