Internal Reflection Spectroscopy Research Articles

Infrared Spectroscopy Study of Edge Water Penetration at Hydrophilic Bonding Interface

Hydrophilic wafer bonding is a process used to bond two wafers without adding material between the two surfaces. Water has a definite impact both during the bonding (bonding wave propagation, adhesion) (1) and after annealing (mechanical strength of the bonding interface, adherence) (2) during such a process. To have a better understanding of mechanisms ruling direct hydrophilic wafer bonding, it is thus important to quantify the amount of water present at the bonding interface.It is known that water is able to penetrate at the bonding interface at room temperature and 40% relative humidity. This has been demonstrated by analyzing defects with scanning acoustic microscopy (SAM) and from X-Ray Reflectivity (XRR) measurements (3,4). Kinetics observed by Tedjini et al. were consistent with a Lucas-Washburn flow through a one nm gap driven by the capillary forces of the hydrophilic surfaces.Nevertheless, no investigation of this phenomenon was performed using Fourier Transform Infra-Red Multiple Internal Reflection (FTIR-MIR) spectroscopy (5). Infrared spectroscopy of silanols, hydrogen bonded water and free water is well documented (6–8) and provides knowledge about water content and organization at the bonding interface. Here FTIR-MIR spectroscopy yields a direct measurement of the relative amount of water and its structure at the interface.More precisely this study will enable us to compare Si-Si, Si-SiO2 and SiO2-SiO2 water penetration kinetics at a fixed distance from the edge of the bonded substrates. A schematic view of the FTIR-MIR setup is shown in Figure 1 to explain the measurement principle.We report the study of water kinetics penetration at bonding interface by FTIR-MIR characterization. A Gaussian decomposition of the OH stretching absorption band signal allows identifying the contributions of silanols, surface bonded water and free liquid water as shown on Figure 2. The integral of each Gaussian peak is otherwise proportional to the relative amount of water. Surface preparation will be discussed and results compared to other characterizations techniques.REFERENCES Larrey V, Mauguen G, Fournel F, Radisson D, Rieutord F, Morales C, et al. Adhesion Energy and Bonding Wave Velocity Measurements. ECS Transactions. 23 sept 2016;75(9):145-52.Fournel F, Tedjini M, Larrey V, Rieutord F, Morales C, Bridoux C, et al. Impact of Water Edge Absorption on Silicon Oxide Direct Bonding Energy. ECS Transactions. 23 sept 2016;75(9):129-34.Tedjini M, Fournel F, Moriceau H, Larrey V, Landru D, Kononchuk O, et al. Interface water diffusion in silicon direct bonding. Appl Phys Lett. 12 sept 2016;109(11):111603.Rieutord F, Tardif S, Landru D, Kononchuk O, Larrey V, Moriceau H, et al. Edge Water Penetration in Direct Bonding Interface. ECS Trans. 24 août 2016;75(9):163-7.Rochat N, Olivier M, Chabli A, Conne F, Lefeuvre G, Boll-Burdet C. Multiple internal reflection infrared spectroscopy using two-prism coupling geometry: A convenient way for quantitative study of organic contamination on silicon wafers. Appl Phys Lett. 2 oct 2000;77(14):2249-51.Baum M, Rébiscoul D, Juranyi F, Rieutord F. Structural and Dynamical Properties of Water Confined in Highly Ordered Mesoporous Silica in the Presence of Electrolytes. J Phys Chem C. 30 août 2018;122(34):19857-68.Caër SL, Pin S, Esnouf S, Raffy Q, Ph. Renault J, Brubach JB, et al. A trapped water network in nanoporous material: the role of interfaces. Physical Chemistry Chemical Physics. 2011;13(39):17658-66.Davis KM, Tomozawa M. An infrared spectroscopic study of water-related species in silica glasses. Journal of Non-Crystalline Solids. 2 juin 1996;201(3):177-98. Figure 1

Infrared Spectroscopy Study of Edge Water Penetration at Hydrophilic Bonding Interface

In this article, we report on the use of a new characterization technique to measure the water penetration at the bonding interfaces and to quantify it. This complements previous studies done using X-ray reflectometry and surface acoustic microscopy: Fourier Transform Infra-Red Multiple Internal Reflection (FTIR-MIR) spectroscopy is used here to characterize the evolutions of contributions of silanols, surface bonded water and free liquid water groups.

Microscopic and Structural Studies of an Antimicrobial Polymer Film Modified with a Natural Filler Based on Triterpenoids.

The aspects of component visualization of the antimicrobial triterpenoids (betulin) additive, both on the surface and in the bulk of the polymer, constituting food film packaging, are considered. This paper presents new knowledge about the morphology and surface structure of modified films using three independent methodological approaches: optical microscopy; a histological method adapted to packaging materials; and a method of attenuated total internal reflection (ATR) spectroscopy in the infrared region with Fourier transform. The use of these methods shows the betulin granules, individual or forming chains. To visualize the antimicrobial additive in the polymer bulk, a modified histological method adapted for film materials and attenuated total internal reflection (ATR) spectroscopy in the infrared region were used with Fourier transform using a Lumos Bruker microscope (Germany) (ATR crystal based on germanium). Sample sections were analyzed using Leica 818 blades at an angle of 45 degrees. The histological method consists of the study of a biological object thin section, in the transmitted light of a microscope, stained with contrast dyes to reveal its structures, and placed on a glass slide. In the method modified for the present study, instead of a biological one, a synthetic object was used, namely the developed film materials with the addition of natural organic origin. Individual granules are about 2 µm long; chains can be up to 10 µm long. The thickness of the granules ranged from 1 to 1.5 microns. It can be seen that the depth distribution of granules in the film from the inner surface to the outer one is rather uniform. Spectroscopic studies using the method of automatic ATR mapping in the region of 880 cm−1 made it possible to evaluate the distribution of an antimicrobial additive based on triterpenoids on the surface and in the polymer bulk.

Influence of oxygen plasma treatment on structural and spectral changes in silica-coated gold nanorods studied using total internal reflection microscopy and spectroscopy.

This paper shows how oxygen plasma treatment affects the structural, localized surface plasmon resonance (LSPR) spectral, and spatial orientation changes in single gold nanorods coated with a mesoporous silica shell (AuNRs@SiO2) in comparison with bare AuNRs with the same aspect ratio (AR). Single AuNRs@SiO2 subjected to different plasma treatment times were characterized using scanning electron microscopy and total internal reflection scattering (TIRS) microscopy and spectroscopy. The AR of the single AuNRs without a silica shell was decreased by structural deformation, while their LSPR linewidth was increased with increasing plasma treatment time. In contrast, single AuNRs@SiO2 showed much higher structural and spectral stability due to the silica shell under the energetic plasma treatment. Furthermore, there was no noticeable variation in the three-dimensional (3D) orientations of single AuNR cores in the silica shell before and after the plasma treatment. The results support that no significant structural and spectral changes occur in single AuNRs@SiO2 and that the silica coating enhances the stability of AuNR cores against oxygen plasma treatment. Therefore, fundamental information on the relationship among plasma treatment time, structural change, LSPR damping, and defocused orientation patterns is provided at the single-particle level.

Scanning Near-Field Optical Nanospectrophotometry: a New Method for Nanoscale Measurements of the Absorption Spectra of Single Nanoobjects

A new experimental method for nanoscale measurements of the absorption spectra of single nanoobjects has been developed based on scanning near-field optical microspectroscopy (SNOM) and nanospectrophotometry (NSP). The main distinctive feature of the proposed SNOM-NSP technique consists in depositing a sample onto a coverglass followed by its probing in the total internal reflection spectroscopy mode. This approach allows the number of analyzed samples to be significantly increased and provides the possibility of combining measurements with other optical techniques. The proposed SNOM-NSP method has been successfully used for studying single plasmonic nanoparticles and their complexes with Rhodamine 6G dye.

Сканирующая ближнепольная оптическая наноспектрофотометрия: метод наномасштабного измерения спектров поглощения единичных нанообъектов

AbstractA new experimental method for nanoscale measurements of the absorption spectra of single nanoobjects has been developed based on scanning near-field optical microspectroscopy (SNOM) and nanospectrophotometry (NSP). The main distinctive feature of the proposed SNOM-NSP technique consists in depositing a sample onto a coverglass followed by its probing in the total internal reflection spectroscopy mode. This approach allows the number of analyzed samples to be significantly increased and provides the possibility of combining measurements with other optical techniques. The proposed SNOM-NSP method has been successfully used for studying single plasmonic nanoparticles and their complexes with Rhodamine 6G dye.

Dual-prism based terahertz time-domain attenuated total reflection spectroscopy and its application to characterise the hydration state of L-threonine in solution

To investigate the hydration state of amino acids, terahertz time-domain attenuated total internal reflection (THz TD-ATR) spectroscopy is often adopted to measure the complex permittivity. However, the classical THz TD-ATR spectroscopy system has only a single ATR prism and requires prism cleaning for different measuring modes, increasing the time consumed and easily introducing errors due to the changing environment. To accelerate the measurements and avoid the influence of environmental fluctuations, in this paper, we designed and built a dual-prism based THz TD-ATR spectroscopy: two ATR prisms with and without samples setting on the optical rail can be sequentially switched to optical systems for easily and rapidly collecting both sample and reference ATR spectra. According to the measurements of deionised water, the dual-prism based THz TD-ATR spectroscopy system can measure the sample complex permittivity rapidly and with high accuracy. The complex permittivity of L-threonine in aqueous solution is measured and analysed via the proposed system, and the hydration numbers of L-threonine solutions in different concentrations are quantitatively characterised. It is believed that the dual-prism based THz TD-ATR technique is a powerful tool for quickly and accurately investigating the hydration of amino acids.

The occurrence, soil parameters and genesis of rubified soils (‘Fuchserden’) of northeastern Germany

The local occurrence of red subsoils on the Late Pleistocene sandy deposits of the Northern European lowlands invites investigation into the formation and paleoenvironmental significance of these soils. According to the World Reference Base for Soil Resources (WRB), these soils are classified as Rhodic Brunic Arenosols or Chromic Brunic Arenosols; however, because of their unclear origins, these soils are still not considered in the German Guidelines for Soil Mapping. We aim to characterize the genesis of these rubified soils by combining pedological findings with chemical analyses and micromorphological studies at four sites in southeastern Brandenburg, Germany. Our novel analytical approach differentiates pedogenic iron (hydr-)oxides using a combination of Fourier transform infrared-multiple internal reflection (FTIR-MIR) spectroscopy and sequential sample heating (from 21 °C to 100 °C, 250 °C, 500 °C, and 950 °C). Together with a comparison of synthetic iron (hydr-)oxides, the results of this analytical approach demonstrate that the mineralogy of these Rhodic Brunic Arenosols and Chromic Brunic Arenosols are characterized mainly by hematite; some goethite and minor amounts of maghemite are also present. Our results confirm recent findings from Jankowski (2013) that rubification is not primarily a relict process in Central European soils; consequently, the German Guidelines for Soil Mapping require revision. The high total iron contents in the rubified soils suggest strongly that the iron is allochthonous in origin, emphasizing the importance of lateral inputs of iron compounds in the genesis of these soils. This finding is highly consistent with the ‘translocation catena’ concept (Sommer and Schlichting, 1997); i.e., the Rhodic Brunic Arenosols and Chromic Brunic Arenosols studied here formed due to inputs of allochthonous compounds. These rubified soils examined in this study share some genetic features with other soils described from Central Europe, such as the ‘Lockerbraunerden’ or the ‘Ockererden’. Further research should focus on these commonalities and compare the genetic pathways of such soils to support the argument that these soils should be considered in a separate soil class in the German Guidelines for Soil Mapping.

In Situ Measurements of Water Content for Sub-Surface Planetary Applications Using Near-Infrared Internal Reflection Spectroscopy (IRS) with a Multimode Optical Fiber.

Results and analysis of internal reflection spectral absorbance experiments are reported for near-infrared (NIR) spectra obtained using an optical fiber sensor system. We present a preliminary study to diagnose the efficacy of our fiber optic system to observe and distinguish various phases of water, i.e., ice, liquid, and adsorbed. This study was motivated by the need for a technique capable of obtaining soil water content measurements in real time and in situ, at low humidity conditions for simulation studies of planetary bodies such as Mars. Spectral signatures were observed for the solid, liquid, and adsorbed phases of water. For all phases, peak absorbance at λ ≈1.45 and 1.94 μm was observed despite slight peak shifting due to dispersion effects. Dispersion effects commonly obscure spectra obtained with internal reflection spectroscopy for particular spectral regions. Here we report a spectral region with minimal distortions. Internal reflection spectra were compared directly to transmission spectra with only slight variations. Spectral matching was performed to determine sample penetration depths for unknown incidence angles. In general, relative absorbance and spectral shifting can distinguish spectra of the various phases of water.

Highly Sensitive Terahertz Thin-Film Total Internal Reflection Spectroscopy Reveals in Situ Photoinduced Structural Changes in Methylammonium Lead Halide Perovskites

Terahertz (THz) thin-film total internal reflection (TF-TIR) spectroscopy is shown to have an enhanced sensitivity to the vibrational properties of thin films in comparison with standard THz transmission spectroscopy. This increased sensitivity was used to track photoinduced modifications to the structure of thin films of methylammonium (MA) lead halide, MAPbI3–xBrx (x = 0, 0.5, 1, and 3). Initially, illumination strengthened the phonon modes around 2 THz, associated with Pb–I stretch modes coupled to the MA ions, whereas the 1 THz twist modes of the inorganic octahedra did not alter in strength. Under longer term illumination, the 1 THz phonon modes of encapsulated films slowly reduced in strength, whereas in films exposed to moisture and oxygen, these phonons weaken more rapidly and blue-shift in frequency. The rapid monitoring of environmentally induced changes to the vibrational modes afforded by TF-TIR spectroscopy offers applications in the characterization and quality control of the perovskite thin...

Oxidation Behavior of Zirconium Diboride Nanoparticles

The products of oxidation of ZrB2 powders with average particle sizes of ~100 and ~30 nm by atmospheric oxygen under isothermal conditions and during heating have been characterized by thermal analysis, X-ray diffraction, scanning electron microscopy, IR frustrated total internal reflection spectroscopy, energy dispersive X-ray analysis, and elemental analysis. The oxidation onset has been observed at 594 and 396°C, respectively. Oxidation at temperatures of ≥800°C leads to the formation of boron oxide and monoclinic ZrO2, independent of the particle size of ZrB2. The reaction rate constants for the oxidation of ZrB2 nanoparticles ~100 and ~30 nm in size have been determined to be 0.03, 0.15, and 0.31 h–1 at 600, 650, and 700°C and 0.11, 0.35, and 0.81 h–1 at 500, 600, and 700°C, respectively. The apparent activation energies for the oxidation of the ZrB2 nanoparticles ~100 and ~30 nm in size are 161 ± 4 and 62 ± 3 kJ/mol, respectively, as evaluated from the temperature dependence of the rate constants at the above temperatures.

Plasmonic Sensing with 3D Printed Optics.

Three-dimensional (3D) printing has undergone an exponential growth in popularity due to its revolutionary and near limitless manufacturing capabilities. Recent trends have seen this technology utilized across a variety of scientific disciplines, including the measurement sciences, but precise fabrication of optical components for high-performance biosensing has not yet been demonstrated. We report here 3D printing of high-quality, custom prisms by stereolithography that enable Kretschmann-configured plasmonic sensing of bacterial toxins. Simple benchtop polishing procedures render a smooth surface that supports propagation of surface plasmon polaritons with a deposited gold layer, which exhibit high bulk refractive index sensitivities and are capable of discriminating trace levels of cholera toxin on a supported lipid membrane interface. Further evidence of the flexibility of this manufacturing technique is demonstrated with printed prisms of varied geometries and in situ monitoring of nanoparticle growth by total internal reflection spectroscopy. This work represents the first example of 3D printed light-guiding sensing platforms and demonstrates the versatility and broad perspective of 3D printing in optical detection.

Electric field standing wave effects in internal reflection and ATR spectroscopy

We investigate electric field standing wave effects in the system semiinfinite incidence medium with high index of refraction/layer/vacuum, the latter being the semiinfinite exit medium. If the layer has a lower index of refraction than the incidence medium, then very strong resonances occur between the two critical angles of the system defined by the systems incidence medium/layer and incidence medium/vacuum, as the layer is then a cavity. In particular close to the lower critical angles, the evanescent fields extend strongly into the exit medium. Based on this effect we suggest two new spectroscopic modalities, namely interference-enhanced internal reflection Raman spectroscopy and interference-enhanced attenuated total reflection infrared spectroscopy.

Influence of the degree of neutralization of acrylic acid and cross-linking agent on optical properties and swelling of sodium polyacrylate

Optical characteristics of polymerization products under variable degrees of neutralization of acrylic acid (AA) and cross-linking agent and at a fixed content of redox components have been studied by IR spectroscopy of frustrated total internal reflection and THz spectroscopy. The results of the analysis show that absorption of IR radiation and dispersion of THz radiation for the samples under study depend on the degree of AA neutralization, which predetermines the mechanism of structure formation of hydrogels, refractive index, and degree of their limited swelling. It is found that the dependences of the refractive index of dry compact hydrogels and the degree of limited swelling of ground polymer samples on the content of neutralizing agent in solutions of the reaction systems have a symbatic character.

Iron Oxide Surface Chemistry: Effect of Chemical Structure on Binding in Benzoic Acid and Catechol Derivatives

The excellent performance of functionalized iron oxide nanoparticles (IONPs) in nanomaterial and biomedical applications often relies on achieving the attachment of ligands to the iron oxide surface both in sufficient number and with proper orientation. Toward this end, we determine relationships between the ligand chemical structure and surface binding on magnetic IONPs for a series of related benzoic acid and catechol derivatives. Ligand exchange was used to introduce the model ligands, and the resultant nanoparticles were characterized using Fourier transform infrared-attenuated internal reflectance spectroscopy, transmission electron microscopy, and nanoparticle solubility behavior. An in-depth analysis of ligand electronic effects and reaction conditions reveals that the nature of ligand binding does not solely depend on the presence of functional groups known to bind to IONPs. The structure of the resultant ligand-surface complex was primarily influenced by the relative positioning of hydroxyl and carboxylic acid groups within the ligand and whether or not HCl(aq) was added to the ligand-exchange reaction. Overall, this study will help guide future ligand-design and ligand-exchange strategies toward realizing truly custom-built IONPs.

Oxidation behavior of TiB2 micro- and nanoparticles

The oxidation of TiB2 particles (75 to 1500 nm in size) has been studied at temperatures of up to 1000°C by thermogravimetry, X-ray diffraction, X-ray photoelectron spectroscopy, IR frustrated total internal reflection spectroscopy, and energy dispersive X-ray analysis. The oxidation onset was observed between 210 and 475°C, depending on the particle size. This distinction can presumably be accounted for in terms of the deformation produced by the Laplace pressure. Oxidation at temperatures under 1000°C leads to the formation of the rutile phase of TiO2 and boron oxide (B2O3). Moreover, at a temperature of ≃ 1000°C titanium borate, TiBO3, was observed to form. Under all of the conditions examined, the oxidation reaction does not reach completion and the oxidation products contain unreacted TiB2.

Measuring optical anisotropy in poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) films with added graphene

Graphene is a 2D nanomaterial having a great potential for applications in electronics and optoelectronics. Composites of graphene with conducting polymers have shown high performance in practical devices and their solution-processability enables low-cost and high-throughput mass manufacturing using printing techniques. Here we measure the effect of incorporation of graphene into poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to the optical anisotropy, absorbance and conductivity of the film. Uniaxial anisotropy in PEDOT:PSS films has been thought to be caused by the spin-coating process used in fabrication. We have characterized spray- and spin-coated films using ellipsometry and total internal reflection spectroscopy, the latter especially for films too thick and uneven for ellipsometry, and show that spray-coating, similar to inkjet printing, also produces consistently anisotropic properties even in very thick and uneven films. Possible plasmonic excitations related to graphene are not seen in the films. The optical and electrical anisotropy of graphene/PEDOT:PSS enables routes to high performance devices for electronics, photonics and optoelectronics.

Surface modification of electrospun PAN nanofibers by amine compounds for adsorption of anionic dyes

Within the present study, polyacrylonitrile (PAN) nanofibers were produced by electrospinning technique. The surface of the webs was then modified by three different sources of amine-containing compounds, including diethylamine, diethylenetriamine, and triethylenetetramine. Chemical, morphological, and surface properties of nanofibers were investigated by attenuated total internal reflection (ATR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. The maximum grafting yield of amine groups to PAN nanofibers was calculated by the gravimetric method. The ATR results indicated that amide groups were formed on the fiber surface by a chemical reaction between the nitrile groups of PAN and the amine groups of amine-containing compounds. The SEM images showed a rough, conglutinated, and intertwined surface morphology of nanofibers induced by amine-containing materials. The AFM results showed that after the functionalization process, the surfaces of the PAN nanofiber were rougher when compared with untreated PAN nanofiber. Finally, their dye removal ability was evaluated using UV–vis spectroscopy using Direct red 80 (DR80) and Direct red 23 (DR23) as model compounds. The amounts of the dye adsorbed onto the functionalized PAN nanofibers (FPAN) were influenced by the initial pH, FPAN dosage, contact time, and the initial concentration of the dye solutions. It was found that both dyes adsorption followed the Langmuir isotherm. In addition, adsorption kinetics of both dyes was found to conform to pseudo-second-order kinetics. We finally found that the functionalized PAN nanofibers were good candidates for anionic dye adsorption from colored wastewater with high dye adsorption capacity

Broadband Plasmonic Photocurrent Enhancement in Planar Organic Photovoltaics Embedded in a Metallic Nanocavity

A substantial broadband increase in the external quantum efficiency (EQE) of thin‐film organic photovoltaic (OPV) devices using near‐field coupling to surface plasmons is reported, significantly enhancing absorption at surface plasmon resonance (SPR). The devices tested consist of an archetypal boron subpthalocyanine chloride/fullerene (SubPc/C60) donor/acceptor heterojunction embedded within a planar semitransparent metallic nanocavity. The absorption and EQE are modeled in detail and probed by attenuated total internal reflection spectroscopy with excellent agreement. At SPR, the EQE can be enhanced fourfold relative to normal incidence, due to simulated ninefold enhancement in active layer absorption efficiency. The response at SPR is thickness‐independent, down to a few monolayers, suggesting the ability to excite monolayer‐scale junctions with an EQE of ≈6% and a 16‐fold absorption enhancement over normal incidence. These results potentially impact the future design of plasmonically enhanced thin‐film photovoltaics and photodetectors and enable the direct analysis of the dynamics of photocurrent production at OPV heterojunctions.

Total internal reflection spectroscopy for studying soft matter

Total internal reflection (TIR) spectroscopy is a widely used technique to study soft matter at interfaces. This tutorial review aims to provide researchers with an overview of the principles, experimental design and applications of TIR spectroscopy to enable them to understand how this class of techniques might be used in their research. It also highlights limitations and pitfalls of TIR techniques, which will assist readers in critically analysing the literature. Techniques covered include attenuated total reflection infrared spectroscopy (ATR-IR), TIR fluorescence, TIR Raman scattering and cavity-enhanced techniques. Other related techniques are briefly described.