Michel Kazan

Abstract: The resonances of phonon and plasmon modes make the absorbance coefficient of materials tremendously high in the mid-infrared spectral range, which allows for a mid-infrared excitation laser to heat the surface layers of these materials with high efficiency. Furthermore, phonon scattering by defects and defect-induced localized vibrational modes affect the local infrared dielectric function and, hence, the local infrared absorption coefficient. In this paper, we present a mid-infrared photothermal beam deflection technique that takes advantage of the strong interaction between infrared optical excitations and vibrational modes to measure the thermal diffusivity of materials without any sample preparation and takes advantage of the strong dependence of the infrared complex dielectric function on defects to detect subsurface defects with high sensitivity. We demonstrate the importance of the developed technique by measuring the thermal properties of highly transparent and reflective samples and detecting defects undetectable with any of the existing optical methods. Namely, using the developed technique, we find that the thermal diffusivities of high-quality Si, crystalline AlN, and crystalline α-SiO2 substrates are 1.00 ± 0.05, 0.67 ± 0.02, and 0.09 ± 0.01, respectively, and we record highly resolved images of structural subsurface defects as well as defects produced by ion-implantations at a depth of 62 μm under the surfaces of 4H-SiC substrates.

TL;DR: Fourier transform infrared reflectivity measurements were used to deduce the effective response in reflection of the investigated system and transversal and longitudinal energy-loss functions were extracted and attributed to transverse and longitudinal resonance modes frequencies.

TL;DR: In this paper, the effect of Ge, deposited on Si(111) substrates prior to the 3C-SiC growth, on the stoichiometric composition of 3CSiC thin layers with Ge amount range from 0 to 1 ML.

TL;DR: In this article, germanium (Ge) has been deposited at the interface between cubic phase silicon carbide (3C)-SiC thin films and silicon (Si) substrates prior to the carbonization process in order to create a Si pseudo-substrate with modified lattice parameters suitable for epitaxial growth of high quality 3C-SiC.