Nonlinear optical mapping of silicon carbide polytypes in 6H-SiC epilayers

Meyer, C.; Lüpke, G.; Kamienski, E. Stein von; Gölz, A.; Kurz, H.

doi:10.1063/1.117141

Cited by 15 publications

(11 citation statements)

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“…The properties of the second-order nonlinear susceptibility of SiC have been analyzed recently in several detailed theoretical papers [11][12][13][14], with a few experimental works [21][22][23][24] demonstrating the potential of secondharmonic generation for the investigation of a broad class of SiC samples [21,22], including SiC nanopowders [23,24]. In our experiments, we have studied both second-and third-order optical nonlinearities of SiC/PMMA nanocomposite films.…”

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confidence: 99%

Generation of the second and third harmonics of femtosecond Cr: forsterite laser pulses in SiC/PMMA nanopowder films

et al. 2003

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Second-and third-harmonic generation in silicon carbide (SiC) nanopowders embedded in a polymethyl methacrylate (P MMA) film are studied using nano-, pico-, and femtosecond laser pulses. Second-and third-harmonic generation processes are shown to allow the detection of absorptive agglomerates of nanocrystals in transparent materials and the visualization of optical breakdown in nanocomposite materials. Polarization of the third-harmonic signal is shown to be highly sensitive to the polarization of the pump field, permitting third-harmonic generation to be used as a probe for the anisotropy of nanocomposite materials. The second-harmonic signal, on the contrary, has no memory of the initial polarization state of the pump field and is, consequently, ideally suited as a measure of orientation-averaged nonlinearities of nanopowder materials. Second-harmonic yield, arb. un. Nanoscale nonlinear optics [1] unveils the fundamental aspects of light-nanostructured matter interactions and gives recipes for designing new materials and creating novel devices for laser physics, nonlinear optics, and ultrafast photonics. Nonlinear optics also offers equally elegant and convenient methods to understand many of fundamental properties of micro-and nanostructured matter [2,3]. Harmonic-generation and wave-mixing processes have been shown to offer new solutions in nonlinear microscopy. In particular, third-harmonic generation (THG) proved to be a very useful tool for a microscopy of biological objects [4,5] and plasmas [6]. It would be a challenging task to extend the ideas of nonlinear-optical imaging to nanoscale systems by applying harmonic-generation and wave-mixing techniques to the visualization of assemblies of nanocrystals and nanoparticles and analysis of nanocomposite materials.

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confidence: 99%

Generation of the second and third harmonics of femtosecond Cr: forsterite laser pulses in SiC/PMMA nanopowder films

et al. 2003

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“…The fourfold symmetry dominates the twofold symmetry, because bulk contributions tend to dominate the surface contributions due to the longer interaction length in the case of bulk when compared to surfaces consisting of only a few atomic layers26.…”

Section: Resultsmentioning

confidence: 99%

“…Electroluminescence was used for imaging luminescent defects in PiN diodes in situ , during forward biasing, and ex situ , after degradation of the diodes 22 23 . Another optical technique, second harmonic generation (SHG) is known to be a rapid, noninvasive and sensitive investigation method used to identify different polytypes 24 and structural defects in SiC epilayers 25 , to map microcrystalline inclusions of SiC polytypes in 6H-SiC epilayers 26 and to probe the crystalline order of 3C-SiC films grown on (111) Si substrates by rotational anisotropy measurements 27 .…”

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confidence: 99%

“…By combining the SHG-based imaging with XRD 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. If in previous publications 24 25 26 27 optical SHG and especially SHG rotational anisotropy were used to detect polytype inclusions, identify different SiC polytypes, or determine crystalline properties for SiC film surfaces, in the present work we emphasize on its potential in high resolution imaging and in structural defect identification. In the same time, because defects detection and identification in SiC require high resolution surface characterization, AFM combined with SHG microscopy were employed so as to provide the topography of the samples needed to locate the defects imaged by SHG.…”

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Nonlinear optical imaging of defects in cubic silicon carbide epilayers

Hristu

Stanciu

Trancă

et al. 2014

Sci Rep

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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.

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“…In terms of non-linear-optical tensor properties, this implies that not only frequency dependence measurements but also polarization studies can provide information on the properties of these materials and can be employed to characterize samples by distinguishing, for example, one polytype from another or by detecting the presence of SiC in a substrate or a thin film. The properties of the second-order nonlinear susceptibility of SiC have been analyzed recently in several detailed theoretical papers, 37,38 with a few experimental studies 39 -42 demonstrating the potential of SHG for the investigation of a broad class of SiC samples, 39,40 including SiC nanopowders 41 and SiC nanocrystal-doped polymers. 42 Much less is known, however, about the third-order optical non-linearities of SiC and only a few experiments on cubic susceptibility-controlled THG in SiC nanocomposite samples have been reported so far.…”

Section: Introductionmentioning

confidence: 99%

Anomalous behavior of the second and third harmonics generated by femtosecond Cr:forsterite laser pulses in SiC–polymer nanocomposite materials as functions of the SiC nanopowder content

Konorov

Akimov

Ivanov

et al. 2003

J Raman Spectroscopy

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Femtosecond pulses of 1.25 µm Cr:forsterite laser radiation were used to study second-and thirdharmonic generation in silicon carbide nanopowders embedded in a poly(methyl methacrylate) (PMMA) film. Harmonic generation processes extend the analytical and sensing abilities of light-scattering techniques, including Raman spectroscopy, offering a convenient and efficient approach to the analysis of nanocomposite materials where nanoparticles tend to agglomerate, masking informative features in Raman spectra. The second-and third-harmonic yields are shown to display an anomalous, counterintuitive behavior as functions of the SiC nanopowder content in a polymer film. Whereas harmonic generation in polymer films with a high content of SiC nanocrystals is quenched by the absorption of agglomerating nanoparticles, the influence of absorption is less detrimental in nanocomposite films with a lower SiC content, leading to the growth of the second-and third-harmonic yields. Nanocomposite films with a lower SiC content are also characterized by a higher breakdown threshold, allowing pump pulses with higher fluences to be applied for more efficient harmonic generation.

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Nonlinear optical mapping of silicon carbide polytypes in 6H-SiC epilayers

Cited by 15 publications

References 1 publication

Generation of the second and third harmonics of femtosecond Cr: forsterite laser pulses in SiC/PMMA nanopowder films

Generation of the second and third harmonics of femtosecond Cr: forsterite laser pulses in SiC/PMMA nanopowder films

Nonlinear optical imaging of defects in cubic silicon carbide epilayers

Anomalous behavior of the second and third harmonics generated by femtosecond Cr:forsterite laser pulses in SiC–polymer nanocomposite materials as functions of the SiC nanopowder content

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