Spatial characterization of Doped Sic Wafers

1998 ◽  
Vol 512 ◽  
Author(s):  
J. C. Burton ◽  
L. Sun ◽  
M. Pophristic ◽  
J. Li ◽  
F. H. Long ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Carrier Concentration ◽  
Raman Spectra ◽  
Longitudinal Optical ◽  
Plasmon Mode ◽  
Nitrogen Doped ◽  
Spatial Characterization ◽  
Sic Wafer

ABSTRACTRaman spectroscopy has been used to investigate wafers of both 4H-SiC and 6H-SiC. The wafers studied were semi-insulating and n-type (nitrogen) doped with concentrations between 2.1 × 1018 cm−3 and 1.2 × 1019 cm−3. Significant coupling of the A1 longitudinal optical (LO) phonon to the plasmon mode was observed. The position of this peak shows a direct correlation with the carrier concentration. Examination of the Raman spectra from different positions on the wafer yielded a rudimentary spatial map of the carrier concentration. This data is compared with a resistivity map of the wafer. These results suggest that Raman spectroscopy of the LO phonon-plasmon mode can be used as a noninvasive, in situ diagnostic for SiC wafer production and substrate evaluation.

Characterization of Redox States of Nickel Hydroxide Film Electrodes by In Situ Surface Raman Spectroscopy

1988 ◽  
Vol 135 (4) ◽  
pp. 885-892 ◽  
Author(s):  
Johann Desilvestro ◽  
Dennis A. Corrigan ◽  
Michael J. Weaver
Keyword(s):  
Raman Spectroscopy ◽  
Nickel Hydroxide ◽  
Redox States ◽  
Hydroxide Film

In Situ Atomic Force Microscopy Tip-Induced Deformations and Raman Spectroscopy Characterization of Single-Wall Carbon Nanotubes

Nano Letters ◽  
2012 ◽  
Vol 12 (8) ◽  
pp. 4110-4116 ◽  
Author(s):  
P. T. Araujo ◽  
N. M. Barbosa Neto ◽  
H. Chacham ◽  
S. S. Carara ◽  
J. S. Soares ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals BCAbox Algorithm Expands Capabilities of Raman Microscope for Single Organelles Assessment

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 106 ◽  
Author(s):  
Andrey N. Kuzmin ◽  
Artem Pliss ◽  
Alex Rzhevskii ◽  
Adrian Lita ◽  
Mioara Larion
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Live Cells ◽  
Spectroscopy Instrumentation ◽  
Precise Analysis ◽  
Express Analysis ◽  
Immediate Analysis ◽  
Software Toolbox ◽  
Cellular Organelles

Raman microspectroscopy is a rapidly developing technique, which has an unparalleled potential for in situ proteomics, lipidomics, and metabolomics, due to its remarkable capability to analyze the molecular composition of live cells and single cellular organelles. However, the scope of Raman spectroscopy for bio-applications is limited by a lack of software tools for express-analysis of biomolecular composition based on Raman spectra. In this study, we have developed the first software toolbox for immediate analysis of intracellular Raman spectra using a powerful biomolecular component analysis (BCA) algorithm. Our software could be easily integrated with commercial Raman spectroscopy instrumentation, and serve for precise analysis of molecular content in major cellular organelles, including nucleoli, endoplasmic reticulum, Golgi apparatus, and mitochondria of either live or fixed cells. The proposed software may be applied in broad directions of cell science, and serve for further advancement and standardization of Raman spectroscopy.

Prototype Raman Spectroscopic Sensor for in Situ Mineral Characterization on Planetary Surfaces

1998 ◽  
Vol 52 (4) ◽  
pp. 477-487 ◽  
Author(s):  
Alian Wang ◽  
Larry A. Haskin ◽  
Enriqueta Cortez
Keyword(s):  
Raman Spectroscopy ◽  
Planetary Surfaces ◽  
Detailed Characterization ◽  
Raman Spectroscopic ◽  
Fine Grained ◽  
Target Rock ◽  
Reaction With Water ◽  
Probe Head

Raman spectroscopy has the potential to provide definitive identification and detailed characterization of the minerals that comprise rocks and soils on planetary surfaces. We have designed a probe head for Raman spectroscopy that is suitable for use on a spectrometer deployed by a rover or a lander on the surface of a planet such as Mars, the Moon, or an asteroid. The probe head is lightweight, low power, rugged, and simple. It is based on a tiny distributed feedback diode laser and volume holographic components. A protective shell surrounds the probe head and serves as a mechanical stop for the mechanical arm of a planetary rover or lander during placement of the probe head onto the surface of a rock or soil. Pressing the shell against the rough surface of a target rock or soil also places the sampling objective of the probe head in rough focus, and the probe head is designed to be tolerant of focusing errors of ∼5 mm. A breadboard version of the probe head gave spectra of high quality on clean crystals of diamond, sulfur, calcite, quartz, and olivine. The results are qualitatively comparable to those obtained by using a conventional micro-Raman spectrometer on fine-grained travertine and on difficult specimens of basaltic lavas and impactites whose original mineralogy had been altered by reaction with water and air.

Laser wavelength selection for Raman spectroscopy of microbial pigments in situ in Antarctic desert ecosystem analogues of former habitats on Mars

2002 ◽  
Vol 1 (4) ◽  
pp. 333-348 ◽  
Author(s):  
Howell G.M. Edwards ◽  
Emma M. Newton ◽  
David D. Wynn-Williams ◽  
David Dickensheets ◽  
Chris Schoen ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Laser Wavelength ◽  
Desert Ecosystem ◽  
Nostoc Commune ◽  
Raman Spectrometry ◽  
Desert Ecosystems ◽  
Long Wavelength ◽  
Life On Earth

The vital ultraviolet- (UV-) protective and photosynthetic pigments of cyanobacteria and lichens (microbial symbioses) that dominate primary production in Antarctic desert ecosystems auto-fluoresce at short wavelengths. We therefore use a long-wavelength (1064 nm) infrared laser for non-intrusive in situ Raman spectrometry of their ecologically significant compounds (especially pigments). To confirm that the power loss at this longer wavelength is justified to avoid swamping by background fluorescence, we compared Raman spectra obtained with excitation at 1064, 852, 830, 785, 633 and 515 nm. These are typical of lasers used for Raman spectroscopy. We analysed communities of the cyanobacterium Nostoc commune and the highly pigmented lichens Acarospora chlorophana and Caloplaca saxicola. These require screening compounds (e.g. pigments such as scytonemin in cyanobacteria and rhizocarpic acid in the fungal symbiont of lichens). They are augmented by quenching pigments (e.g. carotenoids) to dissipate the energy of free radicals generated by penetrating UV. We also analysed organisms having avoidance strategies (e.g. endolithic communities within translucent rocks, including the common cyanobacterium Chroococcidiopsis). These require accessory pigments for photosynthesis at very low light intensities. Although some organisms gave useable Raman spectra with short-wavelength lasers, 1064 nm was the only excitation that was consistently excellent for all organisms. We conclude that a 1064 nm Raman spectrometer, miniaturized using an InGaAs detector, is the optimal instrument for in situ studies of pigmented microbial communities at the limits of life on Earth. This has practical potential for the quest for biomolecules residual from any former surface life on Mars.

Nondestructive Characterizations of Au-Catalyzed GaAs Nanowires on GaAs(111)B Substrates via Identifications of 1st Order Optical Phonon Modes Using μ-Raman Spectroscopy

2020 ◽  
Vol 20 (7) ◽  
pp. 4358-4363
Author(s):  
Jeung Hun Park ◽  
Richard S. Kim ◽  
Se-Jeong Park ◽  
Gye-Choon Park ◽  
Choong-Heui Chung
Keyword(s):  
Raman Spectroscopy ◽  
Dose Rate ◽  
Raman Spectra ◽  
Optical Phonon ◽  
Longitudinal Optical ◽  
Transverse Optical ◽  
Longitudinal Optical Phonon ◽  
Phonon Modes ◽  
Gaas Nanowires ◽  
Beam Dose

We report the relation between the catalyst patterning conditions and the intensity of the 1st order Raman active modes in Au-catalyzed GaAs nanowire bundles. We fabricated e-beam lithographically Au-patterned GaAs(111)B substrates by varying the patterning conditions (e-beam dose rate, dot-size and interdot-spacings), and grew GaAs nanowires via vapor–liquid–solid process using a solid-source molecular beam epitaxy. To understand the effects of the substrate preparation conditions and resulting morphologies on the optical characteristics of 1st order transverse optical and longitudinal optical phonon modes of GaAs, we characterized the nanowire bundles using complementary μ-Raman spectroscopy and scanning electron microscopy as a function of the e-beam dose rate (145–595 μC/cm2), inter-dot spacing (100 and 150 nm) and pattern size (100 and 150 nm). Ensembles of single crystalline GaAs nanowires covered with different Au-thickness exhibit a downshift and asymmetric broadening of the 1st order transverse optical and longitudinal optical phonon peaks relative to GaAs bulk modes. We also showed that the sensitivity of a downshift and broadening of Raman spectra are directly related to morphological and surface coverage variations in as-grown nanowires. We observed clear increases of the transverse optical and longitudinal optical intensity as well as the relatively higher peak shift and broadening of Raman spectra from the 100 nm patterning in response to the dose rate change. Strong dependence of Raman spectra of the nanowire bundles on the e-beam dose rate changes are attributed to the variations in spatial density, size, shape and random growth orientation of the wires. We have shown that the identification of the changes in GaAs longitudinal optical and Arsenic anti-site peaks is good indicators to characterize the quality of as-grown GaAs nanowires. Our finding confirms the utilization of Raman spectroscopy as a powerful tool for characterizing chemical, structural, and morphological information of as-grown nanowires within the supporting substrate.

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