Improved transparent conductive oxide/p⁺/i junction in amorphous silicon solar cells by tailored hydrogen flux during growth

We use the contact potential (Kelvin probe) method to evaluate the electrostatic potential profile across the transparent conductive oxide/p/i junction in hydrogenated amorphous silicon photovoltaic cells. Si films are deposited using reactive magnetron sputter deposition; the atomic H flux to the growth surface is controlled by changing the rate of H₂ injection. H tailoring can be used to minimize the chemical reduction of SnO₂, to optimize the contact potential with ZnO, to maximize the doping efficiency of the p⁺-layer, and to minimize the defect density at the p⁺/i interface. These methods should improve the built-in potential and thus raise the output voltage of amorphous silicon photovoltaic cells.