Pulsed-plasma spatial modulation of i-layer structures and oxygen impurity profiles of hydrogenated amorphous silicon solar cells

In this study, the spatial distribution of the [Si]/[H] content, the refractive index n, the absorption coefficient α, the bandgap E _g, and [O] impurities of hydrogenated amorphous silicon (a-Si:H) solar cells were modulated using pulsed plasma. High n and α, high E _g, and low [O] values had the strongest effects on the aforementioned cells’ short-current density J _sc, open-circuit voltage V _oc, and fill factor FF, respectively. Variations in the [O] profile considerably changed the electric field distribution and the quantity of photogenerated carriers collected. A reduction in the concentration of [O] impurities considerably enhanced the electric field strength in the rear i-layer region and increased the collection of long-wavelength photogenerated carriers. The spatial modulation of a thin buffer i-layer with a high E _g value and low [O] content at the p/i interface was effective in increasing V _oc and FF to improve the efficiency of a-Si:H solar cells.