Visible light emission from single layer Si nanodots fabricated by laser irradiation method

Abstract

A single layer of dense (>1011cm−2) Si nanodots on an insulating a-SiN layer was fabricated by the method combining the laser irradiation on the ultrathin amorphous Si films and subsequent thermal annealing. Raman scattering spectroscopy, planar and cross-section transmission electron microscopy were employed to characterize the formation of Si nanodots. It was found that the size of formed Si nanodots is strongly influenced by the initial amorphous Si film thickness. Visible light emission was observed from the obtained Si nanodots at room temperature and the luminescence peak is varied from 660to725nm with increasing the amorphous Si film thickness. The variable luminescence can be attributed to the interface state assisted radiative recombination rather than the quantum size effect.