Modulation of the photoluminescence spectrum by depth selective excitation of an embedded Si-nc layer

Silicon nanocrystals (Si-nc) were produced by the implantation of Si + in excess into amorphous quartz and a 1 µm SiO 2 film thermally grown on an Si substrate. In the latter, the photoluminescence (PL) spectra from the Si-nc, induced by Ar + laser excitation, are modulated by Fabry–Perot type interference fringes due to the interference of the emitted light reflected at the Si/SiO 2 interface with that propagating directly towards the surface. In this paper, we investigate the spectral modulation and the PL as a function of the incidence angle of the pump laser and the Si + dose implantation. The modulation of the PL spectra is influenced by the distribution in depth of the pump laser intensity in the SiO 2 layer, the depth distribution of the Si-nc and the refractive index distribution of the layered structures. One goal of our work is to modulate the emission spectra by acting on the thickness of the SiO 2 layer. Simulations have been undertaken to establish a relation between the modulation of the PL spectrum and the depth distribution of both the pump laser intensity and the Si-nc. This study required the precise measurements of the depth distribution of both the complex refractive index ( n , k ) by ellipsometry and the Si-nc by transmission electron microscopy (TEM).