Silicon rich oxide powders by HWCVD: Its optical and morphological properties

•Silicon Rich Oxide Powder with photoluminescence was deposited by HWCVD technique.•The evolution of the morphology, that it was observed by SEM.•The dependence of the morphology by the growth temperature was appreciated.•The size of the agglomerates regulates the density of Si-nc and defects.

The effect of the growth temperature on the optical and structural properties of silicon rich oxide powders (SROP) deposited by hot wire chemical vapor deposition is studied. Different microscopic and spectroscopic characterization techniques were used, as photoluminescence (PL), Raman spectroscopy, scanning electron microscope (SEM) and UV–Vis spectroscopy. The powders emit a wide PL spectrum, and the maximum emission peak shows a strong intensity as the growth temperature increases. The SROP deposited at 449 °C showed the most intense peak in PL at 592 nm. The morphology of SROP samples grown at 449 °C revealed the presence of grains with a big size product of coalescence. In low temperatures, the micrographs show small grains, similar to the frost, which it was shown by SEM. The Raman analysis shows that the SROP samples are amorphous except for the growth temperature of 449 °C which exhibit both amorphous and crystalline phases. UV–Vis spectra were used to determinate the optical band gap using the Kubelka–Munḱs (K–M) method. Diffuse reflectance (DR) spectra showed a wavelength-shift of the absorption edge, indicating an increase in the energy optical band gap, when the growth temperature decreases. According to these results, we have studied and analysed the evolution of the morphology of the SROP due to the supersaturation of the environment by the precursors, which affects the intensity of PL, the absorption edge in UV–Vis and the energy optical band gap.

Graphical abstractThe powders emit a wide PL spectrum, and the maximum emission peak shows a strong intensity as the growth temperature increases. The SROP deposited at 449 °C showed the most intense peak in PL at 592 nm. The morphology of SROP samples grown at 449 °C revealed the presence of grains with a big size product of coalescence. In low temperatures, the micrographs show small grain, similar to the frost.Figure optionsDownload full-size imageDownload as PowerPoint slide