OPTICAL TCO PROPERTIES AND QUANTUM EFFICIENCIES IN THIN-FILM SILION SOLAR CELLS

摘要

In superstrate solar cells, certain surface textures of the transparent conducting oxide (TCO) frontelectrode cause efficient light absorption by an antireflective (AR) effect, due to refractive index grading, and lightscattering for elongated optical path lengths and light trapping. Haze and root-mean-square roughness areinadequate quantities to quantitatively account for increased absorption and hence enhanced short-circuit currents.The surface morphology needs to be additionally characterized by texture details that involve lateral dimensions,such as the power spectral densities and angularly resolved power distributions scattered into the absorber layerunder large angles. Based on this hypothesis, identical p-i-n cells of -Si were deposited on several series ofdifferently sputter-deposited and texture-etched ZnO, as well as on Asahi SnO2, and the short-circuit currents wereevaluated in terms of haze, power spectral density, and angularly resolved scattered power.