Crystallization effect of Al–Ag alloying layer in PL enhancement of ZnO thin film

ZnO/Ag/Al multilayer structures were deposited on glass with different annealing conditions and were compared with as-deposited ZnO thin film. The results show that the alloying effects of the Al–Ag film not only induced different interface mechanisms through annealing, but also improved the optoelectronic properties. The alloying ratio of the Al–Ag film increased with the increasing temperatures. Due to the higher ratio of Al–Ag alloying layer, some atoms diffused into the ZnO matrix at higher annealing temperatures, and the PL of the ZnO thin film was destroyed. Oppositely, at lower annealing temperatures, the Al–Ag alloying layer had a better ratio (Al:Ag = 4:1) which could enhance the PL spectra of the ZnO thin film.