Optical properties and quantum efficiency of <i>a</i>-Si1−<i>x</i>C<i>x</i>:H/<i>a</i>-Si:H solar cells

Abstract

The optical properties of all components of heterojunction solar cells based on hydrogenated amorphous silicon (a-Si:H) have been measured individually. By combining these data with knowledge of the cell geometry, an envelope quantum efficiency curve is generated, being simply the fraction of incident photons absorbed in the i layer of the p-i-n cell. Resultant curves for typical cell dimensions are seen to agree remarkably well with observed values for cells with long minority-carrier collection lengths. The model is then used as a diagnostic tool, and finally is demonstrated to have predictive value in the quest for further optimization of solar-cell performance.