Structural, optical and electrical properties of multilayer stacks ZnO:Al/Ag/ZnO:Al and ZrO₂/Ag/ZrO₂

Abstract

Structural, optical, and electrical properties of multilayer stacks ZnO:Al/Ag/ZnO:Al and ZrO2/Ag/ZrO2 are studied. The stacks are deposited on glass substrates without heating by consecutive r.f. magnetron sputtering of ZnO:Al and Ag or ZrO2 and Ag targets, respectively. The properties of samples as‐deposited and annealed in forming gas atmosphere, at 180 °C for 1 h are compared. The structural properties of the stacks are studied by TEM and SEM images and demonstrate semicontinuous granular structure of the Ag films. The Ag nanograins in ZrO2‐based stacks have a larger size than in the ZnO‐based stacks. The spectra of transmittance and reflectance have bands resulting from interband transitions of d‐shell electrons of Ag atoms and plasma resonance oscillations of free electrons. The sheet resistance of the as‐deposited and annealed stacks is in the range 3.1–8.9 Ω/□ and change slightly after annealing. The deposited stacks have potential for application as a back reflector in thin‐film solar cells for improvement of light harvesting and their efficiency.