Theoretical and Experimental Study of Optical Losses in a Periodic/Quasiperiodic Structure Based on Porous Si-SiO₂

This study investigates the reduction of optical losses in periodic/quasiperiodic structures made of porous Si-SiO2 through a dry oxidation process. Due to their unique optical properties, these structures hold great promise for various optoelectronic applications. By carefully engineering the composition and geometry of the structures, we fabricate periodic/quasiperiodic structures on a quartz substrate using an electrochemical anodization technique and subsequently subject them to dry oxidation at two different temperatures. The structure exhibits two localized modes in the transmission and reflection spectra. Unoxidized and oxidized structures’ complex refractive index and filling factors are determined theoretically and experimentally. Optical characterization reveals that the porous Si-SiO2 structures exhibit lower absorption losses and improved transmission than the pure porous silicon structures. Additionally, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirm the presence of porous Si-SiO2 and reduced silicon content. Our study demonstrates that dry oxidation effectively decreases Rayleigh scattering losses, leading to enhanced optical performance and potential applications in efficient optoelectronic devices and systems based on silicon. For instance, periodic/quasiperiodic structures could soon be used as light-emitting devices inside the field of optoelectronics, adding photoluminescent nanoparticles to activate the localized modes.