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

Abstract

Sandwich structured thin films of silicon nanoparticles embedded in Al2O3 matrices were prepared by using the pulsed laser deposition method. High-intensity photoluminescence (PL) with additional fine structures in the wavelength region of 300-550 nm was observed. There was a dramatic change in intensity 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 structures was observed. The PL mechanism is attributed to quantum confinement within the nanoparticles, while the fine structures arose from the different oxidized states in the Si-Al2O3 interface coupled with the electronic transitions in the silicon nanoparticles.