Disclosed herein are systems, methods, and apparatus for forming low emissivity panels that may include a substrate and a reflective layer formed over the substrate. The low emissivity panels may further include a top dielectric layer formed over the reflective layer such that the reflective layer is formed between the top dielectric layer and the substrate. The top dielectric layer may include a ternary metal oxide, such as zinc tin aluminum oxide. The top dielectric layer may also include aluminum. The concentration of aluminum may be between about 1 atomic% and 15 atomic% or between about 2 atomic% and 10 atomic%. An atomic ratio of zinc to tin in the top dielectric layer may be between about 0.67 and about 1.5 or between about 0.9 and about 1.1.