Polaritonic resonances in 2D silicon photonic crystals

Abstract

Polaritonic resonancies are investigated in 2D silicon photonic crystals. Theoretically unpredicted reduction in the transmittance of electromagnetic radiation and the step formation are observed for wavelengths less than optical period of structures due to directed and decay optical modes formed by macroporous silicon as a short waveguide structure. Prevalence of absorption over reflection of light testify to the polaritonic type band formation. Surface polaritons are formed on decay modes in a silicon matrix or macropore at formation of directed optical modes relatively on macropore or silicon matrix. Absorption, photoconductivity and Raman scattering maxima are determined by a corresponding maximum of a longitudinal component of electromagnetic waves in macroporous silicon structure as short waveguide with a specific surface. Longitudinal component of electromagnetic waves in investigated structure interacts effectively with surface oscillators, and polaritonic resonances in 2D silicon photonic crystals are observed.

Quantum-sized effects in oxidized silicon structures with surface II-VI nanocrystals

“…The main cause of stress is a significant difference in temperature expansion coefficients of Si ( ) and, consequently, a larger volume of phases SiO 2 and SiO x as compared to monocrystalline silicon. The direct optical transition energy of the unstrained silicon surface is 3.38 eV [5]. Thus, the maximum deviation from that of the unstrained silicon surface is 90 meV for samples with the CdS nanocoating and the oxide thickness 30 nm as well as for samples with the ZnO nanocoating with the oxide thickness 15 nm.…”

“…The electroreflectance spectra were measured by the standard electrolytic technique at room temperature. It is evident from the figures that all the electroreflectance spectra correspond to silicon of n-type conductivity, while the electroreflectance spectra of macroporous silicon structures correspond to the surface of p-type conductivity silicon [5] due to its passivation by hydrogen atoms. High-energy Franz-Keldysh oscillations [5] with the photon energy higher 3.6 eV indicate the presence of the built-in electric field for CdS and ZnO nanocrystals on silicon oxide with the thickness 15 and 30 nm (Fig.…”

“…Macroporous silicon is promising material for the development of 2D photonic structures with the required geometry and large effective surface [2,3]. It determines optical and electro-optical characteristics of macroporous silicon structures [4,5]. In [6,7], we investigated the near-IR light absorption oscillations in 2D macroporous silicon structures with surface II-VI nanocrystals and SiO 2 nanocoatings, taking into account the electrooptical Wannier-Stark effect within the strong electric field approximation.…”