Impact of thermal oxidation on the structural and optical properties of porous silicon microcavity

Abstract

We report the structural and optical characterization of one-dimensional porous silicon microcavities. These structures are based on a planar resonator formed by two high-reflectance mirrors separated by a thin active optical spacer. In order to simulate and predict the optical properties of the microcavity, the transfer matrix method is used. A strong correlation between the formation parameters and the reflectance spectra is introduced. The prepared microcavities are exposed to thermal oxidation. The resonance position of the microcavity exhibits a blueshift proportional to the degree of oxidation. Structural changes of the microcavities after oxidation are investigated and analyzed using X-ray diffraction and Raman spectroscopy. The observed shift of characteristic silicon peak is attributed to the reduction of silicon crystallites as the oxidation increases.

Bare Eye Detection of Bacterial Enzymes of Pseudomonas aeruginosa with Polymer Modified Nanoporous Silicon Rugate Filters

“…This blue shift of 57 nm is due to the transformation of Si to SiO 2 , which results in a reduction in the refractive index from 3.5 for Si to 1.4 for amorphous SiO 2 [ 47 ]. Therefore, the shift in the reflectance spectrum upon thermal treatment is consistent with the formation of SiO 2 , in full agreement with previous studies [ 48 , 49 ].…”

“…pSiRF sensors were prepared via electrochemical etching of p-type Si (100) wafers in ethanolic hydrofluoric acid by modulating the current density in a sinusoidal manner. The morphology of a typical pSiRF sensor after the subsequently applied thermal oxidation process [ 48 ] is shown in the top view FESEM micrograph in Figure 1 a. This image shows nanopores that are randomly distributed across the surface.…”

Porous Si-SiO2 based UV Microcavities

“…However, the experimental reflection spectrum with its theoretical reflection spectrum did not show a good agreement. MCs were oxidized at different temperature for 5 minutes and a wavelength shift to low wavelengths was observed 47 .…”

Development and Optimization of Experimental Biosensing Protocols Using Porous Optical Transducers

“…To achieve such SiO 2 layer, several techniques have been applied, such as thermal oxidation or chemical oxidation, being the former the most used. It consists in converting Si into SiO 2 by thermolysis at temperatures below 950°C, to avoid the modification of the shape of the structure [104][105][106] (see Figure 2.13). In this work, pSi was oxidised using a tube furnace CTF 12 (Carbolite Gero Ltd, Sheffield, United Kingdom).…”