A.I. Diaz Cano

Raman-scattering and structure investigations on porous SiC layers

Raman scattering spectroscopy, scanning electron microscopy, and scanning acoustic microscopy were studied on porous SiC layers prepared by different technological routes and subjected to reactive ion treatment. The Raman spectra revealed a number of features specific for nanocrystallite materials, which can be used for characterization and diagnostics of porous SiC layers for technological applications.

Defect related photoluminescence in Si wires

Photoluminescence spectra and their dependence on the temperature have been used to study the peculiarities of the red photoluminescence in low-dimensional Si structures, such as porous silicon and silicon oxide films with an admixture of silicon. It has been shown that red photoluminescence band of Si wires is complex and can be decomposed into two elementary bands. Practically the same positions of photoluminescence bands are observed in silicon oxide films. Comparative investigation of photoluminescence temperature dependence in Si wires and silicon oxide indicates that oxide defect related mechanisms for photoluminescence bands are involved. The photoluminescence excitation mechanisms in both objects are discussed as well.

Photoluminescence and Raman spectroscopy in porous SiC

This paper presents results of porous SiC characterization using photoluminescence, Raman scattering and Atomic Force Microscopy. A comparative optical spectroscopy study on bulk SiC and porous SiC layers has shown a number of new features specific to nano-crystallite materials. The role of these effects on optical spectroscopy data in porous SiC accessed by photoluminescence and Raman scattering is discussed.

Porous SiC layers on Si nanowire surface

The preparation method and characterization data are described for porous SiC layers grown on the surface of porous silicon (P-Si) wires. Raman scattering spectroscopy, energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM) were employed for the characterization. It is shown that in the first approximation, the wire structure of the porous SiC repeats the surface morphology of the porous Si. Some peculiarities of P-SiC surface structure were also observed whose connection with the P-Si surface is not yet clarified. The study of the Raman spectra has permitted to determine the crystalline structure (polytypes) for the SiC layers and shown a feature specific for nano-crystallite materials, which has been analyzed and discussed.

Optical and structural evaluation of SiC nanocrystallites

This paper presents results of the non-contact and non-destructive characterization of porous SiC layers using Raman scattering spectroscopy, scanning electron microscopy as well as atomic force microscopy methods. The comparative study of the Raman spectroscopy on the bulk SiC and porous SiC layers has shown a number of new features specific for nanocrystallite materials, which have been analyzed and discussed.

Exciton Emission Stimulation and Exciton Polariton Coupling in SiC Nanocrystals

The paper presents the results of SiC nanocrystal characterization using photoluminescence spectroscopy technique. Earlier it was shown that original SiC wafers and porous SiC (PSiC) layers have been characterized by 6H-SiC crystal type with inclusions of 4H-, 15R- and 2H- SiC polytypes. The study of photoluminescence in PSiC layers with different nanocrystal (NC) sizes reveals the intensity stimulation for exciton-related PL bands in NCs of different SiC polytypes. The intensity enhancement for exciton-related PL bands is attributed to the exciton recombination rate increasing due to the realization of exciton weak confinement and exciton-polariton coupling in SiC NCs. The numerical simulation has been done for the dependence of exciton recombination rate versus SiC NC sizes at the assumption of exciton-polariton coupling model.