Functionalization control of porous silicon optical structures using reflectance spectra modeling for biosensing applications

Abstract

International audienceModeling and experimental reflectance spectra of porous silicon single layers at different steps of functionalization and protein grafting process are adjusted in order to determine the volume fraction of the biomolecules attached to the internal pore surface. This method is applied in order to control the efficiency of the chemical functionalization process of porous silicon single layers. Using results from single porous silicon layer study, theoretical microcavity is simulated at each step of the functionalization process. The calculated reflectance spectrum is in good agreement to the experimental one. Therefore the single layers study can be applied to multilayer structures and can be adapted for other optical structures such as waveguides, interferometers for biosensing applications

Progress of porous silicon APTES-functionalization by FTIR investigations

“…The functionalization process consists of activating Si and PS surfaces by grafting small organic molecules. The 3-aminopropyltriethoxysilane (APTES) is one of the most frequently used organosilane coupling agents that may connect chemically reactive amino groups on Si and PS substrates [9][10][11][12][13][14]. Silanization of Si wafers and PS layers with organosilanes requires a pre-oxidation step [15][16][17], generally thermal oxidation.…”

Theoretical investigation of Vernier effect based sensors with hybrid porous silicon-polymer optical waveguides

“…Mach-Zehnder interferometers (MZ) have been demonstrated experimentally as surface PSi sensors 6 and in Vernier effect structures with an MR filter or an MZ filter 12 . The MZ structure represented in Figure 3, is composed of two arms: a reference arm and sensor arm which will be exposed to the target molecules (BSA).…”

“…Clearly, PSi is therefore interesting for surface detection, as its high specific surface up to 800 m 2 /cm 3 dramatically increases the waveguide sensitivity for surface detection of specific molecules which are grafted into the pores. 6 A theoretical PSi MR surface sensitivity to Bovine Serum Albumin (BSA) has been calculated up to 0.02 nm/pg/mm 2 . 7 One way to greatly increase the sensitivity of the sensor is to employ the Vernier effect 8 using interferences between two or more interferometers.…”

Nano-structured silicon based lab on a chip for diagnostics

“…Currently, sensors are designed to determine the concentration of various gases, alcohol, moisture, some biological molecules and toxic elements, based on suppression of photoluminescence of nano-porous silicon, interferometer sensors and the effects of thermo acoustic abilities [1][2][3][4][5][6][7].…”