Periodic nanoripples and photoluminescence on ZnO:Al film induced by femtosecond laser pulses

The periodic nanoripples on ZnO:Al films induced by 800 nm femtosecond laser pulses are prepared. The regularity and formation mechanism of surface periodical nanostructure are studied after it is irradiated by femtosecond laser of different energy flux densities. Using He-Ge laser as light source, the photoluminescence spectra of ZnO:Al films and its relationship with periodical nanostructures are studied. It is shown that the enhancement of emission near the band gap results from the quenching effect by 800 nm femtosecond laser on ZnO:Al films and the increase in optical absorption of He-Ge laser by the nanoripples.