A detailed numerical model of the electronic properties of hydrogenated amorphous silicon has been developed and shown to be a useful tool for the analysis of the performance and optimization of the design of solar cells. The method of simulation involves solving Poissons's equation, and the electron and hole continuity equations, in conjunction with the transport equations for the electrons and holes. From the solutions of these equations we obtained the electrostatic potential, the electron and hole concentrations and the current densities. A set of realistic material parameters has been used. We have modelled the density of states to consist of two exponential band tails and the dangling bonds. Recombination in both the band tails and the dangling bonds has been taken into consideration in the model. We investigated the effect of the cell performance on varying dangling bond densities (10<SUP>16</SUP>cm<SUP>-3</SUP>-10<SUP>17</SUP>cm<SUP>-3</SUP>) for various cell thicknesses of p-i-n hydrogenated amorphous silicon solar cells, for incident blue and red light. Our results agree well with experiments for solar cells in the undegraded state. However for the degraded state the fill factors appear to be higher than the experimental values. This might be because we have only assumed a single level dangling bond density in our model. It is suggested that future work might undertake the incorporation of the spatial dependence of the dangling bond density in the model.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:638814 |
| Date | January 1995 |
| Creators | Shariff, A. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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