Query: Area-framing optical defect review under optical resolution using  multi-NA dark-field microscopy images 

Candidate papers:

abstract: Metrology and inspection (MI) processes are established at critical points of the semiconductor manufacturing process in order to maintain a certain yield and also provide information needed for future processes improvements. Typically, the inspection consists of dark field (DF) inspection and SEM review/classification processes. An optical DF microscopy system (or inspection tool) first detects particles or pattern defects on wafers and obtains their position coordinates. However, due to its limited optical resolution, the DF system is not widely applied in the review process, which requires higher resolution images of the detected defects such as those provided by scanning electron microscopy (SEM) but with a sacrifice of throughput. We propose an innovative idea of applying two (or three) dark field microscopy images for intermediate defect classification and size estimation under optical resolution. The proposed method utilizes the angular scattering distribution from a defect that is in the Mie scattering domain, which varies depending on both the beam and defect properties (wavelength, polarization, incident angle; shape, size, complex refractive index) It captures three darkfield images of the same wafer by three inter changeable objectives with different magnification and numerical aperture (NA) values under identical side illumination conditions. We estimate the defect types and sizes simply by investing three measurements. We demonstrated this proposed method to classify and estimate the defect size down to 80nm by an existing UV inspection tool with three DF imaging modes; 1) M15 mode, sampling stance 150 nm, NA =0.6, 2) M25 mode, sampling distance 250 nm, NA=0.36, and 3) M40 mode, sampling distance =400 nm, and NA =0.23. We demonstrated its feasibility by an independent SEM measurement of the detected defects.
author_names: Jun Ho Lee

Junhee Jeong

Shin-Woong Park

Hwi Kim

Byeong Geon You
title: Area framing optical defect review under optical resolution using multi NA dark field microscopy images
venue: Advanced Lithography
year: 2019

abstract: Nanoscale contaminants (including engineered nanoparticles and nanoplastics) pose a significant threat to organisms and environment. Rapid and non destructive detection and identification of nanosized materials in cells, tissues and organisms is still challenging, although a number of conventional methods exist. These approaches for nanoparticles imaging and characterisation both inside the cytoplasm and on the cell or tissue outer surfaces, such as electron or scanning probe microscopies, are unquestionably potent tools, having excellent resolution and supplemented with chemical analysis capabilities. However, imaging and detection of nanomaterials in situ, in wet unfixed and even live samples, such as living isolated cells, microorganisms, protozoans and miniature invertebrates using electron microscopy is practically impossible, because of the elaborate sample preparation requiring chemical fixation, contrast staining, matrix embedding and exposure into vacuum. Atomic force microscopy, in several cases, can be used for imaging and mechanical analysis of live cells and organisms under ambient conditions, however this technique allows for investigation of surfaces. Therefore, a different approach allowing for imaging and differentiation of nanoscale particles in wet samples is required. Dark field microscopy as an optical microscopy technique has been popular among researchers, mostly for imaging relatively large specimens. In recent years, the so called "enhanced dark field" microscopy based on using higher numerical aperture light condensers and variable numerical aperture objectives has emegred, which allows for imaging of nanoscale particles (starting from 5 nm nanospheres) using almost conventional optical microscopy methodology. Hyperspectral imaging can turn a dark field optical microscope into a powerful chemical characterisation tool. As a result, this technique is becoming popular in environmental nanotoxicology studies. In this Review Article we introduce the reader into the methodology of enhanced dark field and dark field based hyperspectral microscopy, covering the most important advances in this rapidly expanding area of environmental nanotoxicology.
author_names: Rawil F Fakhrullin

Laysan Nigamatzyanova

Golnur Fakhrullina
title: Dark field/hyperspectral microscopy for detecting nanoscale particles in environmental nanotoxicology research.
venue: The Science of the total environment
year: 2021

abstract: X ray dark field imaging (XDFI) utilizing a thin silicon crystal under Laue case enables visualizing three dimensional (3D) morphological alterations of human tissue. XDFI uses refraction contrast derived from phase shift rather than absorption as the main X ray image contrast source to render 2D and 3D images of tissue specimens in unprecedented detail. The unique features of XDFI are its extremely high sensitivity (approximately 1000:1 compared to absorption for soft tissues under X ray energy of around 20 keV, theoretically) and excellent resolution (8.5 mm) without requiring contrast medium or staining. Thus, XDFI computed tomography can generate 3D virtual histological images equivalent to those of stained histological sections pathologists observe under low power light microscopy as far as organs and tissues selected as samples in preliminary studies. This paper reviews the fundamental principles and the potential of XDFI, describes two optical setups for XDFI with examples, illustrates features of XDFI that are salient for histopathology, and presents XDFI examples of refraction contrast images of atherosclerotic plaques, musculoskeletal tissue, neuronal tissue, and breast cancer specimens. Availability of this X ray imaging in routine histopathological evaluations of tissue specimens would help guide clinical decision making by highlighting suspicious areas in unstained, thick sections for further sampling and analysis using conventional histopathological techniques. XDFI is a promising tool for 3D virtual histopathology.
author_names: Daisuke Shimao

Naoki Sunaguchi

Tetsuya Yuasa

Masami Ando

Kensaku Mori

Rajiv Gupta

Shu Ichihara
title: X ray Dark Field Imaging (XDFI) a Promising Tool for 3D Virtual Histopathology
venue: Molecular Imaging and Biology
year: 2021

abstract: Scanning Probe Microscopy (SPM) has emerged as a metrology solution for the semiconductor industry enabling high throughput defect review and high resolution 3D metrology. TNO has developed a Subsurface Ultrasonic Resonant Force Microscopy (SSURFM) for non destructive, high resolution imaging of features buried under one or more layers of material. Challenging targeted applications for this technique are overlay metrology and wafer alignment through optically opaque layers and overlay and alignment on product features, which requires device resolution. Using the TNO SSURFM technique, sub surface measurements on two overlay and alignment targets have been performed. The goal of this study is to show the potential of the technique for Overlay/Alignment Applications.
author_names: Maarten H van Es

Hamed Sadeghian Marnani

M J van der Lans
title: Subsurface Ultrasonic Resonant Force Microscopy for Image based Overlay Measurement
year: 2019

abstract: Near field microscopy breaks the diffraction limit and probes the image at subwavelength resolution by exploiting the properties of evanescent wave near the sample under study. Its implementation in the microwave frequency range, scanning microwave microscopy (SMM) has recently attracted more attention as it brings radio frequency and microwave measurements down to the molecular and atomic scale. Currently, the modeling of SMM and quantification of local material properties of samples usually neglects radiation and scattering losses of the nano sized probe based on low frequency assumptions. To improve numerical accuracy of SMM modeling and evaluate existing models, we have applied a rigorous full wave numerical model with all wave components in the near field taken into consideration. In virtue of the proposed full wave model, several approximations presented in previous studies are validated, and we conclude that the SMM has potential for use as a broadband dielectric spectroscopy operating at even higher frequencies. (c) 2017 Optical Society of America OCIS codes: (180.4243) Near field microscopy; (260,2110)Electromagnetic optics;(350.4010) Microwave References and links 1. Imtiaz, A. et al. "Frequency selective contrast on variably doped p type silicon with a scanning microwave microscope," Journal of Applied Physics 111, 093727 (2012) 2. Lai, K. et al. "Mesoscopic percolating resistance network in a strained manganite thin film," Science 329, 190 193 (2010) 3. Tselev, A. et al."Near field microwave scanning probe imaging of conductivity inhomogeneities in cvd graphene," Nanotechnology 23, 385706 (2012) 4. Plassard, C.et al."Detection of defects buried in metallic samples by scanning microwave microscopy," Physical Review B. 83, 121409 (2011) 5. Lai, K. Ji, M. 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"Tomographic effects of near field microwave microscopy in the investigation of muscle cells interacting with multi walled carbon nanotubes," Applied Physics Letters 101, 203101 (2012) 17. Binnig, G. Quate, C. F. Gerber, C."Atomic force microscope," Physical review letters 56, 930 (1986) 18. Binnig, G. Rohrer, H. "Scanning tunneling microscopy," Surface science 126, 236 244 (1983) 19. Anlage, S. M. Talanov, V. V. Schwartz, A. R. "Principles of near field microwave microscopy," In Scanning probe microscopy, 215 253 (Springer, 2007) 20. Wei, T. Xiang, X. D. Wallace Freedman, W. Schultz, P. "Scanning tip microwave near field microscope," Applied Physics Letters 68, 3506 3508 (1996) 21. Gao, C. Xiang, X. D. "Quantitative microwave near field microscopy of dielectric properties," Review of scientific instruments 69, 3846 3851 (1998) 22. Talanov, V. V. Scherz, A. Moreland, R. L. Schwartz, A. R. "A near field scanned microwave probe for spatially localized electrical metrology," Applied physics letters 88, 4105 (2006) 23. Omarouayache, R. Payet, P. Raoult, J. Chusseau, L. "Millimeter wave near field imaging with bow tie antennas," Optics express 23, 12144 12151 (2015) 24. TAupfer, F. Dudorov, S. Oberhammer, J. "Millimeter wave near field probe designed for high resolution skin cancer diagnosis," IEEE Transactions on Microwave Theory and Techniques 63, 2050 2059 (2015) 25. Chisum, J. D. Popovic, Z. "Performance limitations and measurement analysis of a near field microwave microscope for nondestructive and subsurface detection," IEEE Transactions on Microwave Theory and Techniques 60, 2605 2615 (2012) 26. Gramse, G. et al. "Calibrated complex impedance and permittivity measurements with scanning microwave microscopy,"Nanotechnology 25, 145703 (2014) 27. Lai, K. Kundhikanjana, W. Kelly, M. Shen, Z. "Modeling and characterization of a cantilever based near field scanning microwave impedance microscope,"Review of scientific instruments 79, 063703 (2008) 28. Belov, Pavel A. and Yang Hao. "Subwavelength imaging at optical frequencies using a transmission device formed by a periodic layered metal dielectric structure operating in the canalization regime." Physical Review B 73.11 (2006) 113110. 29. Hao, Yang, and Raj Mittra."FDTD modeling of metamaterials: Theory and applications," Artech house, 2008. 30. Fumagalli, L. Ferrari, G. Sampietro, M. Gomila, G. "Dielectric constant measurement of thin insulating films at low frequency by nanoscale capacitance microscopy," Applied Physics Letters 91, 243110 (2007) 31. Gomila, G. Gramse, G. Fumagalli, "L. Finite size effects and analytical modeling of electrostatic force microscopy applied to dielectric films," Nanotechnology 25, 255702 (2014) 32. Fumagalli, L. Gramse, G. Esteban Ferrer, D. Edwards, M. Gomila, G. "Quantifying the dielectric constant of thick insulators using electrostatic force microscopy," Applied Physics Letters 96, 183107 (2010) 33. Zhao, J. S. Chew, W. C. "Integral equation solution of maxwellaAZs equations from zero frequency to microwave frequencies," IEEE Transactions on Antennas and Propagation 48, 1635 1645 (2000) 34. Zhu, J. Jiao, D. "A rigorous solution to the low frequency breakdown in full wave finite element based analysis of general problems involving inhomogeneous lossless/lossy dielectrics and nonideal conductors," IEEE Transactions on Microwave Theory and Techniques 59, 3294 3306 (2011) 35. Sarkar, T. K. Djordjevic, A. R. Kolundzija, B. M. Method of moments applied to antennas. In Handbook of Antennas in Wireless Communications, 239 279 (CRC Press, 2001) 36. Sheng, X. Q. Song, W. Essentials of computational electromagnetics, vol. 757 (John Wiley Sons, 2011) 37. Jin, J. M. "The finite element method in electromagnetics," John Wiley Sons, 38. Jiao, D. Xue, L. "Solution to the low frequency breakdown in full wave finite element based analysis of general lossy problems," In 2016 IEEE International Symposium on Antennas and Propagation (APSURSI) 1129 1130 (2016) 39. Yu, C. Fan, S. Sun, Y. Pickwell MacPherson, E." The potential of terahertz imaging for cancer diagnosis: A review of investigations to date," Quantitative imaging in medicine and surgery 2, 33 45 (2012) 40. Klein, L. Swift, C. "An improved model for the dielectric constant of sea water at microwave frequencies," IEEE Transactions on Antennas and Propagation 25, 104 111 (1977) 41. Meissner, T. Wentz, F. J."The complex dielectric constant of pure and sea water from microwave satellite observations," IEEE Transactions on Geoscience and Remote Sensing 42, 1836 1849 (2004) 42. Schneegans, O. Houze, F. Meyer, R. Boyer, L. "Study of the local electrical properties of metal surfaces using an afm with a conducting probe," IEEE Transactions on Components, Packaging, and Manufacturing Technology: Part A 21, 76 81 (1998) 43. Akiyama, K. et al. "Development of a metalaAStip cantilever for noncontact atomic force microscopy," Review of scientific instruments 76, 033705 (2005) 2014) 44. Krupka, J. et al. "Dielectric properties of semi insulating silicon at microwave frequencies," Applied Physics Letters 107, 082105 (2015)
author_names: Q -
title: Full wave broadband modeling ofnear field scanning microwave microscopy
year: 2017

abstract: High resolution electron microscope images can provide us with the configurations of relatively heavy metal atoms in both perfect and disordered crystals directly in some favorable cases. The information available is limited to two dimensional projections. Within this limitation, however, it has been possible to study ordering problems of disordered crystals. As examples we shall describe and interpret the diffuse scattering from disordered crystals of Nb W oxides and incommensurate lattice periodicities in Ta,O, based crystals, illustrating the relationships between diffraction data and the images. Introduction. Distributions of diffuse scattering intensity that arise from imperfections in crystals have long been a major means for the study of order and disorder phenomena in solids. A large number of studies have been done by use of X ray or neutron diffraction techniques and undoubtedly these give the most quantitative results, although electron diffraction is used increasingly to detect and describe the nature of the disorder. The recent development of high resolution.electron microscopy however has shown that the configurations of relatively heavy atoms in crystals can be determined by direct imaging in favorable cases [I] This new technique has beeli used for imaging not only perfectly periodic regions of crystals but also non periodic regions. The high resolution electron microscope images, information in direct space, combined with the. usual electron diffraction data allow us to make the interpretation of diffuse scattering more reliable since diffraction data are averaged over large volumes of crystals. This opens up a new range of possibilities for the study of short range order and of ordering processes even though the method is still seriously limited to two dimensional projections. As one of the present authors pointea out [2] there is the added complication that dynamical diffraction'processes are important for all but the very light atom materials. Hence the~wealth of detail in high resolution images of threedimensionally disordered crystals is,often difficult to interpret. However, careful comparison of the experimental images and the theoretical calculation of image intensities including full dynamical scattering effects makes it possible to some extent to study the nature of such three dimensional disorders. This method has been applied to the study of the disorders in crystals of GeNb,02, [3] On the other hand images of two dimensionally disordered crystals having linear and planar defects parallel to the incident beam can often be interpreted readily in spite of dynamical diffraction effects and can give valuable information on atomic ordering not obtainable by any other method. Various planar defects in some transition metal oxide systems have been studied and important roles of the defects in oxidation or reduction process of these materials were found [4 51. In particular, for the crystals of Nb,2 x0, it has been found that the non stoichiometry of this crystal is accommodated by linear defects which take the form of chains of defect clusters of oxygen vacancies and niobium interstitial atoms. The formation and ordering processes of these clusters were observed directly at the atomic level of resolution and furthermore the diffuse scattering patterns caused .by the clusters were explained in terms of short range order of the clusters [6 71. In the present paper we shall deal with some disordered crystals of Nb,O, WO, systems and Ta,O, WO, systems and focus on the elucidation of relationships between electron diffraction patterns and high resolution images. For the former samples, the origin of the anomalous diffuse ring patterns appearing around some Bragg spots, which were first observed by Allpress in disordered crystal of 3 Nb20, 8 WO, [8] Article published online by EDP Sciences and available at http:/dx.doi.org/10.1051/jphyscol:1977726 C7 136 S. IIJIMA AND J. M. COWLEY have been investigated by means of optical diffraction model experiments. For the latter materials, we shall discuss incommensurate lattice periodicities which are induced by deficiency of oxygen. Theoretical background of electron microscopy. HIGH RESOLUTION BRIGHT FIELD IMAGES OF CRYSTALS. To interpret the high resolution electron microscope images of crystals, we are required to understand properly both the electron optics of the electron microscope and the electron diffraction phenomena inside the crystals. The former involves various electron optical parameters, such as spherical aberration of the objective lens, chromatic aberration, the divergence angle of the incident electron beam, the objective aperture size, and the focus of the objective lens. These effects on the image intensities have been intensively studied at various laboratories and are fairly well understood [9] Treatment of electron scattering in crystals is the most important part for the study of image formation of crystals because the dynamical effects of scattered electron waves are usually significant. Here crystal thicknesses and alignment of crystal orientations are the most influential parameters for the image intensities. Rigorous calculations of amplitudes and phases of diffracted waves for perfect crystals have been developed at Melbourne and Arizona [lo] The calculations are based on the multi slice formulation of electron diffraction theory due to Cowley and Moodie. Extension of these calculations to two dimensionally disordered crystals has also been made by assuming an artificial superstructure cell which contains a suitably chosen portion of a disordered crystal [ll] Accuracy of the image calculation can be determined by truncation of the number of the diffracted beams excited inside the crystals. From the practical point of view, for the study of crystal defects it has been shown by detailed comparison of experimental images and theoretical calculations that if the images were obtained from the crystals having the thicknesses of less than roughly 50 A, the image intensity distributions may often be interpreted as the ones to be expected under kinematical diffraction conditions, namely when there is a roughly linear relation between the density of scattering matter and image intensities [12] This is the basis for the study of diffuse scattering from disordered crystals of 17 Nb,O, 49 WO, This condition is also the basis for the use of o~tical diffraction exwriments on the model scopy, Cowley [14] suggested that thepretical interpretation of dark field images based on the weak phase object approximation is rarely valid and superposition of the defects or microdomains in the direction of the incident electron beam makes the interpretation difficult. On the other hand, if the disorders occur two dimensionally, so that the crystals remain perfectly periodic in the third direction, the ambiguity arising from such superpositions effects can be eliminated. For this reason, the disordered crystalsof 17 Nb205 49 W03 are ideal test objects to examine properties of the dark field images. Using these crystals we have investigated the limitation of information available from the dark field images. Methods for the theoretical calculation of the dark field images that have been developed in our laboratory will provide further confirmation of the interpretation. ELECTRON MICRODIFFRACTION AND TRANSMISSION ELECTRON MICROSCOPY. In recent years techniques have been developed for obtaining diffraction patterns from very small .identifiable regions of electron microscope specimens. Patterns from areas approaching 20 A in diameter have been obtained using adaptions of both the conventional transmission electron microscope [15] and the scanning transmission electron microscope 1161. With the latter type of instrument the selected areas may well be reduced to 5 A or less in the near future. By these means it should be possible to overcome the difficulty, inherent in the standard selected area diffraction techniques, of obtaining direct correlation between the diffraction pattern and imageof a small region of an imperfect crystal. In studies of short range ordering it has already been shown [16] that diffraction patterns can be obtained from within individual microdomains. The extension of this method to even smaller regions should obviously be valuable. In cases &here the interpretation of image intensities from local atom configurations is ambiguous the microdiffraction pattern should allow the structure to be resolved in greater detail. KINEMATICAL ND PSEUDO KINEMATICAL,SCATTERING FROM, DISORDERED CRYSTALS. We review briefly the kinematical approximation for the scattering from two dimensionally disordered crystals and the pseudokinematical approximation which can provide some account of the dynamical scattering. effects for this crystals having two dimensional disorders. particular case. DARK FIELD IMAGES OF DISORDERED CRYSTALS. A high resolution image of a thin specimen obtained This technique has been widely applied as a means to with the incident beam parallel to a principal axis can observe ordered microdomains in disordered crystals show the projection of the structure. The correspondhaving short range order and microciystallites occuring kinematical amplitude distribution ,in the diffracring in amorphous materials. Using only the diffuse tion pattern is given by the planar sectionaf the Fourier transform function scattering which appear between sharp Bragg spots to form th; image, the microdomains are visualized as F(uv0) C fi exp 2 ni(ux, vy, (1) bright spots [13] For high resolution dark field microi STUDIES OF ORDERING USING HIGH RESOLUTION ELECTRON MICROSCOPY C7 137 where the summation is taken over all atoms in the sample. For a thin crystal which is well ordered in the beam direction the contributions of the n atoms superimposed in that direction fik may be combined to give F(uv0) 1 ji' exp 2 ni(uxi
author_names: Sumio Iijima

John M Cowley
title: II. SHORT RANGE ORDER SUPER IONIC CONDUCTORSSTUDIES OF ORDERING USING HIGH RESOLUTION ELECTRON MICROSCOPY
year: 1977

abstract: The advent of aberration correctors for electron optical lenses at the end of 20th century has brought atomic resolution analysis of the materials into a new era. In this thesis, the new possibilities of application and methodology on aberration corrected analytical transmission electron microscopy (TEM) of light elements in complex oxides are explored by experiments and image simulations, with the emphasis on annular bright field (ABF) imaging. The arrangement and bonding of light elements, like lithium (Li) and oxygen (O) in complex oxides plays a crucial rule in the material's properties, however the characterization of the materials remains challenging. In recent years ABF imaging has become a popular imaging technique owing to its ability to map both light and heavy elements. I start from the application of ABF on qualitatively determining O's distribution in ZrO2 La2/3Sr1/3MnO3 (LSMO) pillar matrix thin films, together with the application of high angle annular dark field (HAADF) and electron energy loss spectroscopy (EELS) to obtain a fuller picture of the investigated complex oxide. After that, the methodology study of ABF imaging, concerning the quantitative determination of atom column position and concentration, is presented. The accuracy of atom column position determination is of great importance for investigating atomic structure defects like elastic and plastic strains. Atomic scale control of the synthesis of complex oxide materials envisages the atomic scale properties and requires the knowledge of atomic scale characterization. The ZrO2 LSMO pillar matrix thin films were found to show anomalous magnetic and electron transport properties controlled by the amount of ZrO2. With the application of an aberration corrected analytical transmission electron microscope (TEM) structure and interfacial chemistry of the system, especially of the pillar matrix interface were revealed at atomic resolution. In addition, three types of Mn segregated antiphase boundaries (APBs) connecting ZrO2 pillars were investigated by HAADF and ABF imaging. The local atomic structure, chemical composition, cation valence and electric field were determined at atomic scale. These results provide detailed information for future studies of macroscopic properties of these materials. Moreover, a consequence of aberration correctors is the high electron dose rate in the scanning mode. This can lead to radiation induced modifications of materials. I studied the electron beam induced reconstruction of three types of APBs. With the utilization of HAADF scanning transmission electron microscopy (STEM) ABF STEM and EELS, the motion of both heavy and light element columns under moderate electron beam irradiation are revealed at atomic resolution. Besides, Mn segregated in the APBs was found to have reduced valence states, which can be directly correlated with oxygen loss. Charge states of the APBs are finally discussed based on these experimental results. This study provides support for the design of radiation engineering solid oxide fuel cell materials. The determination of atom positions from atomically resolved transmission electron micrographs is fundamental for the analysis of crystal defects and strain. Contrast formation in ABF is partially governed by the phase of the electron wave, which renders the technique more sensitive to the tilt of the electron beam with respect to the crystal zone axis than in high angle annular dark field (HAADF) imaging. I show this sensitivity experimentally and use image simulations to quantify this effect. This is essential for future quantitative ABF studies including error estimation. Another aspect of quantification is the number of atoms in an atom column. The attempt to quantify Li concentration by ABF imaging has been done by simulations. The influences of convergence semi angle, collection semi angle, and defocus are explored, while direct correlation with experimental results need more theoretical investigations in this area. Semi quantification of the Li amount was studied by EELS in case of the particle size dependent delithiation process of LiFePO4. From the core loss region and low loss region analysis it is found that the sample with particle size of 25 nm delithiates homogeneously over the whole particle, whereas the 70 nm and 150 nm particles form an FePO4 core and a LiFePO4 shell. The practical considerations, like radiation damage, delocalization, interface effects and so on are also discussed.
author_names: Dan Zhou
title: Aberration Corrected Analytical Transmission Electron Microscopy of Light Elements in Complex Oxides: Application and Methodology
year: 2016

abstract: Single particle optical investigations have greatly improved our understanding of the fundamental properties of nano objects, avoiding the spurious inhomogeneous effects that affect ensemble experiments. Correlation with high resolution imaging techniques providing morphological information (e.g. electron microscopy) allows a quantitative interpretation of the optical measurements by means of analytical models and numerical simulations. In this topical review, we first briefly recall the principles underlying some of the most commonly used single particle optical techniques: near field, dark field, spatial modulation and photothermal microscopies/spectroscopies. We then focus on the quantitative investigation of the surface plasmon resonance (SPR) of metallic nano objects using linear and ultrafast optical techniques. While measured SPR positions and spectral areas are found in good agreement with predictions based on Maxwell's equations, SPR widths are strongly influenced by quantum confinement (or, from a classical standpoint, surface induced electron scattering) and, for small nano objects, cannot be reproduced using the dielectric functions of bulk materials. Linear measurements on single nano objects (silver nanospheres and gold nanorods) allow a quantification of the size and geometry dependences of these effects in confined metals. Addressing the ultrafast response of an individual nano object is also a powerful tool to elucidate the physical mechanisms at the origin of their optical nonlinearities, and their electronic, vibrational and thermal relaxation processes. Experimental investigations of the dynamical response of gold nanorods are shown to be quantitatively modeled in terms of modifications of the metal dielectric function enhanced by plasmonic effects. Ultrafast spectroscopy can also be exploited to unveil hidden physical properties of more complex nanosystems. In this context, two color femtosecond pump probe experiments performed on individual bimetallic heterodimers are discussed in the last part of the review, demonstrating the existence of Fano interferences in the optical absorption of a gold nanoparticle under the influence of a nearby silver one.
author_names: Aurelien Crut

Paolo Maioli

Fabrice Vallee

Natalia Del Fatti
title: Linear and ultrafast nonlinear plasmonics of single nano objects.
venue: Journal of physics. Condensed matter an Institute of Physics journal
year: 2017

abstract: Nanoscopy is a term that we use to describe optical techniques using digital image processing that are capable of nanometric observation and measurement. Laser Scanning Tomography (LST) is used for defect analysis in the bulk of semiconductor wafers for revealing particles as small as mm and for measuring densities of uptolO13 cm3 The unusually high contrast of the system allows us to observe submicron particles which are more than three orders of magnitude smaller than the Rayleigh criterion for the optical system. Recent work using deconvolution of point image functions enables us to perform sub micron optical serial sectioning, for determining the depth of defects. The best conditions for classical LST (using laser illumination perpendicular to the viewing direction) are when operating further than a few microns below the surface in semiconductor wafers; ie it is ideal for bulk defect studies. The study of imperfections inside epilayers in the top ijim layer requires a modified technique. Instead of illuminating at 900 the viewing direction, the infra red laser beam is introduced obliquely to the front suffe to illuminate the defects in the epilayer while still in the dark field mode. Combining this method with high resolution sectioning will be the basis for a technique of three dimensional submicron defect analysis in epilayers. Results are given of defect studies in annealed GaAs and silicon to demonstrate the capabilities of LST for naiiometer analysis in bulk materials. Sub micron depth measurement is shown for single particles using the PSF of the system for the out offocus case. Some initial results are given of studies of defects in a highly lattice mismatched epilayer using IR transmission microscopy, phase stepping microscopy (PSM, used in surface profiling) and the new dark field oblique laser illumination technique. LST, and the new nanoscopy techniques are non destructive, operate under normal room conditions, and give sub micron observation and distance measurement of defects over large areas with the possibility of 3D image synthesis for defect analysis.
author_names: Paul C Montgomery

Pascal Gall-Borrut

Syamsa Moh Ardisasmita

M Castagne

Jacques Bonnafe

J P Fillard
title: Laser scanning tomography and related dark field nanoscopy method
venue: Optics Photonics
year: 1991

abstract: GaAsBi alloys have been extensively studied in recent years, and the highest Bi concentration yet reached has been 22 Many photoelectric devices using this material have been produced, such as quantum well lasers, LEDs, solar cells, etc. The Bi incorporated into AlAs is expected to change the bandgap from indirect to direct. There are only a few theoretical reports on AlAsBi, however, experimental research results are seldom reported. In this chapter, we review the molecular beam epitaxy of GaAsBi and analyze the growth mechanism. Besides, we present the synthesis of AlAsBi by molecular beam epitaxy. The growth temperature, As/Ga flux ratio, Bi flux and the growth rate all have great influence on the Bi incorporation. Bismuth atoms play a surfactant role under As rich conditions and an anti surfactant role under Ga rich conditions. Droplets tend to be formed on the surface of GaAsBi alloys due to the atomic size mismatch between Bi atoms and As atoms. The high angle annular dark field mode of scanning transmission electron microscopy images confirm Bi atoms cluster exsiting in GaAsBi films. Furthermore, we show the optical properties of GaAsBi and discuss the localized states induced by Bi. The photoluminescence wavelength of GaAsBi redshifts with increasing Bi concentration. The bandgap of GaAsBi is insensitive to temperature, which is important for developing un cooled lasers. We discuss the influence of Bi incorporation on the electric and transport properties of GaAsBi. The types of dominant point defects induced by Bi incorporation are analyzed. The measurement results of the electron effective mass demonstrate that Bi incorporation not only changes the valence band but also has non negligible influence on the conduction band in GaAsBi. For AlAsBi, we review the theoretical simulations and present the molecular beam epitaxy growth without substrate rotaion to investigate the influence of As/Al flux raio and the Bi flux on Bi incorporation.
author_names: Li Yue

Xiaolei Zhang

Wei Ou

Zhenghao Shen

Shumin Wang
title: Molecular Beam Epitaxy Growth and Properties of GaAsBi and AlAsBi
year: 2019