Beauty of science: solar cell surface


The image shows the surface of a silicon solar cell viewed under an optical microscope.

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The surface texturing produces triangular pyramidal pits, while the anti-reflective coating gives a blue sheen. Both are designed to maximise photon absorption within the cell structure. The silicon wafer from which this particular cell was manufactured, contains crystallographic twins and grains – regions where the crystal structure is rotated with respect to its surroundings. This is the case in the black area, which is oriented such that the microscope illumination is not reflected.

The shiny, yellow line is a silver front-face electrical contact, the deposition process giving rise to bumps such that it is not possible for the microscope to focus on the whole structure at once.

The structure of solar cells, the defects in the silicon and their correlation with photovoltaic performance are studied at ESRF beamline BM05 using X-ray diffraction imaging.

Top image: Surface of silicon solar cell viewed under an optical microscope (Image credit: T. Lafford/ESRF).