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

Abstract

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).

(Invited) Synthesis and Characterization of Group IV Nanocrystals

“…Numerous articles in the literature describe the interpretation of the luminescence spectra of Si-nc systems. A large number of studies have been performed on the influence of size and distribution (13,28,29), of temperature (30,31), of annealing parameters (32), as well as specific parameters of the synthesis methods (33,34). However, the physical mechanisms of carrier recombination in such nanostructures are still poorly understood.…”

Optical Properties of Femtosecond Laser-Synthesized Silicon Nanoparticles in Deionized Water

“…Recently, Si-NPs have been shown to be able to generate singlet oxygen under irradiation, making them promising candidates for photodynamic therapy. A variety of chemical − and physical − methods have been employed to prepare Si-NPs. Among them, wet chemistry routes are attractive because particle size and surface properties can be controlled simultaneously.…”

A novel approach to the synthesis of photoluminescent germanium nanoparticles by reactive laser ablation

“…For instance, Galli and co-workers have studied the structure and stability of Ge nanoparticles [3], and also the effects of surface reconstruction [4]. Si and Ge nanostructures were synthesized in many ways, including etching, implantation, co-sputtering, sol-gel, laser ablation etc [5][6][7][8][9][10][11][12]. At present the most common method of fabrication of luminescent Ge structures is the synthesis of Ge nanocrystals embedded in a SiO 2 matrix by implantation or sputtering [13][14][15].…”