Near-field scanning optical microscopy and spectroscopy for semiconductor characterization

Hallén, Hans; Rosa, Andrés H. La; Jahncke, C. L.

doi:10.1002/pssa.2211520126

Cited by 24 publications

(14 citation statements)

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“…This leads to new selection rules for surface‐enhanced Raman spectroscopy (SERS) (e.g. see Moskovits, 1985; Creighton, 1988 and references therein), and also to differences between far‐ and near‐field Raman spectroscopy measured with a near‐field optical microscope (Hallen et al. , 1995; Ayars et al ., 2000).…”

Section: Introductionmentioning

confidence: 91%

The effects of probe boundary conditions and propagation on nano‐Raman spectroscopy

Hallén

Ayars

Jahncke

2003

Journal of Microscopy

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Key words. Boundary conditions near a metal, electric field enhancement, gradient-field Raman, KTP, light propagation in the near-field, nano-Raman, near-field Raman spectroscopy, near-field scanning optical microscopy, resolution. SummaryRaman spectra obtained in the near-field, with collection of the Raman-shifted light in reflection, show selective enhancement of vibrational modes. We show that the boundary conditions for an electric field near a metal surface affect propagation of the reflected signal and lead to this selection. The enhancement of certain Raman forbidden vibrations is explained by the presence of an electric field gradient near the metalapertured fibre probe.

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Section: Introductionmentioning

confidence: 91%

The effects of probe boundary conditions and propagation on nano‐Raman spectroscopy

Hallén

Ayars

Jahncke

2003

Journal of Microscopy

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“…Such a line would have the same symmetry as that in the discussion above, although the above 783 cm -1 line is found in many studies and is reported as 'strong,' a criterion common to many of the lines observed in the signal-starved NSOM-Raman. A fairly strong peak at 716 cm -1 has previously been observed in NSOM-Raman with the probe close to the surface, [3,4] but no distance dependent measurements were made. This peak can be explained [20] by the coupling through the electric field gradient to the strong IR absorption line at 712 cm -1 .…”

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confidence: 87%

Surface enhancement in near-field Raman spectroscopy

Ayars

Hallén

2000

Applied Physics Letters

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The intensity and selection rules of Raman spectra change as a metal surface approaches the sample. We study the distance dependence of the new Raman modes with a near-field scanning optical microscope (NSOM). The metal-coated NSOM probe provides localized illumination of a metal surface with good distance control. Spectra are measured as the probe approaches the surface, and the changes elucidated with difference spectra. Comparisons to a theoretical model for Raman excitation by evanescent light near the probe tip indicate that while the general trends are well described, the data show oscillations about the model. PACS Numbers: 78.30.-j, 07.79.Fc, 78.66.-w , 82.80.Ch Table of Contents Category: Optics.The proximity of sharp metallic structures to a sample has profound effects on the Raman spectra of that sample. It leads to surface enhanced Raman spectroscopy (SERS), for example see [1,2] and references within, and to differences between far-field and near-field Raman spectroscopy measured with a near-field optical microscope (NSOM). [3-6] Two aspects of the spectra, the selection rules and the mode intensities, are altered by the presence of the metal. We concentrate in this paper on the dependence of the intensity of the new modes with distance between the metal-coated probe and the dielectric surface. This enhancement originates from the evanescent light present near the probe tip. A model describing the fields near such a small aperture was described by Bethe [7] and later modified by Bouwkamp.[8] Betzig et al. [9] measured the fields near an NSOM tip using single fluorescent molecules as detectors, and found good agreement with this theory. We show in this paper that the theory can also explain the general trends of the experimental enhancements in Raman spectroscopy, but that the data show oscillations about the theoretical curve as the tip approaches the surface.Near-field scanning optical microscopy (NSOM) [10] provides a unique method to study the effects of metal in proximity to the sample under Raman scrutiny. The aluminum-coated probe, forming the NSOM aperture, can be moved with nanometer accuracy to and from the surface. Force feedback of the NSOM is used as an indicator of distance, [11,12] [13] in combination with a calibrated piezoelectric scanner. A cooled (-45° C) CCD camera in the photon counting mode is used in conjunction with a Jarrel-Ash Czerney-Turner spectrometer for the Raman signal detection. An Argon Ion laser operating at 514.5 nm provides the excitation. In this experiment, the sample is illuminated through a tapered fiber probe, which is mounted through the center of a 0.5 N.A. aspheric lens. The backscattered light from the sample is collected and collimated with this lens. The light then passes through a holographic notch filter to remove elastically scattered light before being focused into the spectrometer. The primary difficulty encountered in NSOM-Raman is that of low signal levels. This cannot be countered by increased input intensity, as input of more than a few milliwat...

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“…Plasmonic resonances generate a tightly confined electric field around metallic (e.g., Au and Ag) or semi‐metallic (e.g., graphene) structures . The near‐field mapping of such electric field distributions is the key to understanding the fundamentals of plasmonics . In general, the near‐field scanning optical microscope (NSOM), which relies on a tip‐based enhancement of the scattering, has been a standard in this regard .…”

Section: Photochromic‐isomerization‐induced Directional Mass Migratimentioning

confidence: 99%

“…In general, the near‐field scanning optical microscope (NSOM), which relies on a tip‐based enhancement of the scattering, has been a standard in this regard . However, a conventional NSOM is limited to a mapping of the intensity rather than the field direction and is also plagued by both its requirement for a complicated optical setup and its vulnerability to subtle vibrations . The directional mass migration of azomaterials acts as an alternative route to address the above‐mentioned drawbacks of the conventional NSOM .…”

Section: Photochromic‐isomerization‐induced Directional Mass Migratimentioning

confidence: 99%

Light‐Directed Soft Mass Migration for Micro/Nanophotonics

Kim

Park

et al. 2019

Advanced Optical Materials

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In this review, it is argued that soft mass migrations, driven and guided by spatially controlled photopolymerization and photochromic isomerization (also called directional plastic deformation or photofluidization of azobenzene materials), offer toolsets for optical engineers to develop various micro/nanophotonic materials and devices that are not readily available with conventional lithographic methods and self‐assembly techniques. In this direction, the two seemingly different concepts of (i) photopolymerization and (ii) photochromic‐isomerization‐driven mass migrations are tied together, and then recent technological advances in these two fields are summarized, including diffractive optical elements (DOEs), electro‐optic DOE devices, colorimetric sensors, biologically inspired optics, plasmonic devices and near‐field studies, and exceptional point optics. This review establishes the technological viability of light‐directed soft mass migration for the overall evolving field of micro/nanophotonics and its research perspectives.

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Near-field scanning optical microscopy and spectroscopy for semiconductor characterization

Cited by 24 publications

References 14 publications

The effects of probe boundary conditions and propagation on nano‐Raman spectroscopy

The effects of probe boundary conditions and propagation on nano‐Raman spectroscopy

Surface enhancement in near-field Raman spectroscopy

Light‐Directed Soft Mass Migration for Micro/Nanophotonics

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