Relation of TCO surface texture shape to a-Si/μc-Si tandem cell performance on W-texture SnO2:F TCO substrates

Double-texture (W-texture) TCO, which was named “HU-TCO”, has a combination of 300-500nm height and over 1μm width hills which are covered with submicron-size pyramidal texture that leads to high haze value in a wide wavelength range. We studied the relation between the bottom current of the a-Si:H/μc-Si:H tandem solar cells and the TCO texture indexes, such as the haze ratio at 800nm, and light scattering angle distribution. There is a positive correlation between bottom current and haze ratio at 800nm; however it was observed that the bottom current hit a peak at very high haze value. We modified amorphous p-layer of top cell and confirmed that the player configuration strongly affected Voc. Appropriate player configuration not only affected the Voc but also further increased the bottom current on the HU-TCO with high hills.