The effect of atmospheric annealing on the photoluminescence of sandwich-structured thin films of silicon nanoparticles embedded in Al2O3 matrices

Sandwich-structured thin films of silicon nanoparticles embedded in Al2O3 m atrices were prepared by using the pulsed laser deposition method. High-int ensity photoluminescence (PL) with additional fine structures in the wavele ngth region of 300-550 nm was observed. There was a dramatic change in inte nsity of the main PL peak with different annealing conditions, and its peak position was gradually blue-shifted with increasing annealing temperature of the samples. However, no corresponding blue-shift of the PL fine structu res was observed. The PL mechanism is attributed to quantum confinement wit hin the nanoparticles, while the fine structures arose from the different o xidized states in the Si-Al2O3 interface coupled with the electronic transi tions in the silicon nanoparticles.