Nonlinear optical imaging of defects in cubic silicon carbide epilayers

Abstract

Silicon carbide is one of the most promising materials for power electronic devices capable of operating at extreme conditions. The widespread application of silicon carbide power devices is however limited by the presence of structural defects in silicon carbide epilayers. Our experiment demonstrates that optical second harmonic generation imaging represents a viable solution for characterizing structural defects such as stacking faults, dislocations and double positioning boundaries in cubic silicon carbide layers. X-ray diffraction and optical second harmonic rotational anisotropy were used to confirm the growth of the cubic polytype, atomic force microscopy was used to support the identification of silicon carbide defects based on their distinct shape, while second harmonic generation microscopy revealed the detailed structure of the defects. Our results show that this fast and noninvasive investigation method can identify defects which appear during the crystal growth and can be used to certify areas within the silicon carbide epilayer that have optimal quality.

One‐Pot Route to Gold Nanoparticles Embedded in Electrospun Carbon Fibers as an Efficient Catalyst Material for Hybrid Alkaline Glucose Biofuel Cells

“…The strong relative intensity of the (111) peaks compared to the diffractograms of the carbonized samples in Figure b can be noticed. This result can be explained either by anisotropy of the sample during analysis in the Bragg Brentano configuration or, more probably, by anisotropy during the initial steps of NP growth, that is, formation of anisotropic gold seeds . Figure a also shows the presence of a peak at 2 θ= 31.6° that is not present in the carbonized fibers (Figure b) or in the crude film that does not contain gold (PAN+DMF) (XRD presented in Figure S2, Supporting Information).…”

Silicon Carbide for Novel Quantum Technology Devices

“…This technique is competitive with destructive sample preparation and severely limited area of analysis to tens of microns associated instead with high-resolution TEM. By combining the SHG-based imaging with X-ray diffraction and SHG rotational anisotropy, the growth of 3C polytype on the 4H-SiC substrate was confirmed, and the polytype of the imaged defects was identified [77].…”

Pixel‐level angular quantification of capsular collagen in second harmonic generation microscopy images of encapsulated thyroid nodules

“…Moreover, SHG microscopy has been used not only for biological and medical samples but also in the materials science field. [ 9–12 ]…”

“…Moreover, SHG microscopy has been used not only for biological and medical samples but also in the materials science field. [9][10][11][12] SHG microscopy provides multiple advantages over confocal fluorescence microscopy [13] : label-free, subfemtoliter volume resolution enabling noninvasive optical 3D sectioning, reduced photobleaching and phototoxicity and deeper tissue imaging. Moreover, due to the coherent nature of the SH signals, the SHG intensity depends on the laser beam polarization and on the structure and organization of the noncentrosymmetric molecules in the investigated sample.…”