ABSTRACTThin films of intermixed layers of In₂O₃:Sn (denoted ITO) and silver were made by reactive dc magnetron sputtering. The silver to indium atomic ratio was 0 ≤ x ≥ 0.09 Films with x = 0.01 showed increased luminous transmittance T_lum after annealing at 100 or 200°C, whereas x > 0.01 yielded lowered T_lum. The optical properties could be reconciled with the Maxwell-Garnett effective medium theory assuming that a well-defined portion of the silver was occluded as spheroidal particles. Films with x ≤ 0.06 had enhanced electrical conductivity after annealing at 200 or 300°C. Transmission electron microscopy displayed columnar features whose character depended on x.