Can fluorine-doped tin Oxide, FTO, be more like indium-doped tin oxide, ITO? Reducing FTO surface roughness by introducing additional SnO₂ coating

Among the commercially common transparent conducting oxides (TCOs) are fluorine-doped tin oxide (FTO) and indium-doped tin oxide (ITO), neither of which meets all criteria for the optimal TCO. Despite its superior chemical stability and being composed of abundant elements, FTO suffers from high surface roughness compared to ITO. Here, we introduce a path to substantially decrease the surface roughness of FTO, while preserving most of its original advantages, by depositing an SnO₂ coating on top of the FTO layer using pulsed laser deposition. Such an enhancement may allow future use of FTO in devices that use now the more expensive, less stable ITO, which contains relatively rare indium.