Impact of Mg and La on the microstructure and properties of silver films used as reflective electrodes

Ag films are ideal materials for optoelectronic applications, but they usually suffer from agglomeration and optoelectronic performance degradation under humid and hot conditions. To improve the hydrothermal performance of Ag, the present research introduced La and/or Mg into Ag and investigated their effects on the microstructure and properties of silver films. Mg and/or La obviously refined the particle size of the Ag films and decreased their surface roughness. The average particle size and RMS roughness of Ag alloyed with 0.4 % Mg and 0.1 % La decreased sharply to 39.7 nm from 94.7 nm to 1.02 nm from 2.63 nm, respectively. A small amount of Mg and/or La can effectively inhibit the agglomeration of Ag under humid and hot conditions, and thus greatly enhance the hydrothermal performance of the Ag film. After the humid heat test, the reflectance and sheet resistance of the silver film sharply decreased to 76.0 % from 95.3 % and increased to 1.1889 Ω/□ from 0.1387 Ω/□, respectively. However, the reflectance and square resistance of the Ag-0.4Mg-0.1La film decreased to 90.1 % and increased to 0.2665 Ω/□, respectively.