Theoretical and Experimental Characterization of Silicon Nanoclusters Embedded in Silicon-Rich Oxide films

Abstract

We present theoretical calculations using DFT method and the Global Reaction Model (GRM) for molecular structures and photoluminescence (PL) and Fourier Transform Infrared (FTIR) spectroscopy for silicon nanoclusters (Si-NCs) embedded in silicon rich oxide (SRO) films. Correlations between theoretical predictions and experimental results are made taking as reference experimental results obtained from measurements performed on SRO thin films obtained by the Hot Filament Chemical Vapor Deposition (HFCVD) technique. Our theoretical predictions are general since they do not depend on the particular technique used to obtain such films but rather the suggested SinOn structures. A good correlation exists for Eg values for films grown at 1300°C corresponding to Si 8 O 8 and Si 16 O 16 molecular structures suggested and for films grown at 1150°C with Si 9 O 9. Regards PL correlation, a film grown at 900°C gives a spectrum peaked at 440nm and 548nm while theoretical one shows peaks at 471nm and 549.8 nm for a structure Si 16 O 16. Such sample with a further annealing displays peaks at 405nm, 749nm and 820nm with theoretical predictions at 415nm using Si 6 O 6. As for FTIR, theoretical calculations predict vibrational mode frequencies of bonds Si-O and Si-H whose values are well located in the experimental frequency range corresponding to the structure Si 16 O 16 .

Natural Rubber Biocomposites Filled with Phyto-Ashes Rich in Biogenic Silica Obtained from Wheat Straw and Field Horsetail

“…By analyzing the spectra of infrared spectroscopy with the Fourier transformation, it was possible to obtain information on the structure of the tested samples in terms of the qualitative composition of the materials. In the case of silicon dioxide, the typical spectrum is characterized by the presence of three bands with maximum peaks at 1100, 800 and 450 cm −1 [ 47 , 48 ]. For all samples of the tested phyto-ashes, analogous maxima were obtained, differing in their surface areas ( Figure 4 ).…”

Use of powder silicon as a photocurable resin filler for laser stereolithography and prospects for transforming stereolithographic parts with silicon from polymeric to ceramic ones.

“…According to experimental and calculated data [20], absorption peaks in the area of 655-677 cm The observed widening of the short-wave wing of 900-1200 cm -1 peak seems to occur due to the appearance of a small absorption peak in the area of 1170 cm -1 , typical for Si-O-C bond [13,21,22].…”