The surface and interface group is responsible for the following experimental infrastructure at CBPF; 

• • AFM-Bruker Multimode 8 (air/liquid)

  • AFM-NTMDT (dedicated for Magnetic Force Microscopy)

  • ZEISS Optical microscope

  • Aarhus-150 STM SPECS

  • VT-STM Omicron 

  • Surface Enhanced Raman UHV system 

  • Home built-Raman spectrometer for polarized/unpolarized studies  

  • Home-built Nanopositing system

  • Contact Angle

  • NAP-XPS

  • FTIR

AFM-Bruker Multimode 8 (air/liquid)

Atomic Force Microscopy (AFM) is a powerful imaging technique that allows for the visualization and characterization of surfaces at the nanoscale. This revolutionary technique has been widely used in various fields such as physics, chemistry, biology, materials science, and nanotechnology.

The basic principle of atomic force microscopy is the interaction between an extremely sharp and fine tip and the surface of the object being investigated. The tip is attached to a flexible cantilever structure that bends in response to intermolecular forces between the tip and the surface. This deflection of the cantilever is detected and recorded, generating a high-resolution three-dimensional image of the object's surface.

One of the main advantages of atomic force microscopy is its ability to operate in different environments, including vacuum, liquids, or even under normal atmospheric conditions. This makes the technique highly versatile and applicable to a wide range of samples, from living cells to inorganic materials.

In addition to topographic imaging capabilities, atomic force microscopy also offers the possibility of performing various modifications and measurements at the nanoscale. For example, it is possible to map the hardness, adhesion, electrical conductivity, and magnetic properties of surfaces, as well as manipulate and assemble individual atoms and molecules.

The Bruker Multimode 8 AFM offers you the possibility to make images of nano-scale surface topography under two conditions, air or liquid. And It has two modes of operation: Contact and Tapping Mode. The imaging size provides three defaults sizes:  256x256, 512x512 and 1024x1024 pixels. As an advantage, the samples do not require previous treatment, and its possible to study all kind of materials/samples.  The principal applications are: Material and Polymer Science, Biological Research, Electrochemistry. 

Our research group has been dedicated to investigating iron oxides, with a focus on preparing flatter surfaces through thermal treatments. Additionally, we explore the adsorption of these samples with starch molecules, aiming to understand the interaction of this system, which is widely used in reverse flotation processes of quartz, a crucial technique in the mining industry. 

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7228

O microscópio de força magnética (MFM) da NT-MDT é uma ferramenta de ponta projetada para realizar medidas magnéticas de alta resolução em amostras a nível nanométrico. Utilizando uma ponta magnética extremamente sensível, o MFM é capaz de mapear e caracterizar campos magnéticos locais com precisão, revelando informações detalhadas sobre a distribuição e as propriedades magnéticas das amostras.

Este equipamento é especialmente útil para estudar materiais magnéticos, tais como filmes finos, nanoestruturas magnéticas, e dispositivos magneto-ópticos. Ele permite a visualização das variações do campo magnético na superfície da amostra, identificando regiões com diferentes direções e intensidades magnéticas. Além disso, o MFM da NT-MDT pode ser utilizado para investigar fenômenos magnéticos em sistemas complexos, como interfaces de materiais e estruturas magnéticas em nanoescala.

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7228

Um microscópio óptico é um instrumento que utiliza luz visível ou outra radiação eletromagnética para ampliar e visualizar amostras em uma escala macroscópica. Ele é amplamente utilizado em diversos campos científicos e industriais devido a várias vantagens. Em comparação com microscópios de força atômica, os microscópios ópticos são mais rápidos e corriqueiros em suas medidas, permitindo uma análise mais rápida de amostras. Além disso, os microscópios ópticos são capazes de medir diferentes tipos de amostras, sejam elas planas ou em pó, oferecendo uma versatilidade maior em termos de aplicação e amostragem. No entanto, sua resolução é limitada pela difração da luz, o que impede a visualização de estruturas abaixo de certas dimensões. 

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7228

STM Aarhus 150 form SPECS

The laboratory has a STM Aarhus 150 form SPECS that allows observing processes on surfaces in nanometers scale. It has a desing with the lowest mechanical loop between tip and surface, resulting in extreme stability and fast scan rate are obtained by high resonant frequencies. The SPECS STM 150 Aarhus has a rapid approach mechanism for approach speeds of more than 1mm/min.  The tip can be cleaned by parallel ion beam corrosion, field emission without need for tip replacement.  

In our laboratory. Falar um pouco sobre o que estamos fazendo (Sulfetação e liquid valve)

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7448

VT STM Omicron

The Omicron VT SPM is a well established microscope in many research labs for Scanning Probe Microscopy. It won the prominent R&D award in 1996. To date more than 500 instruments have been delivered and successfully installed around the world. The volume of research results and publications is a conclusive proof to the performance, quality, and versatility of the Variable Temperature SPM design.  This STM was donated by the Fritz Haber Institute Max-Planck-Gesellschaft to CBPF and is being commissioned.

Falar mais duas linhas

ErLEED 3000

Low Energy Electron Diffraction (LEED) is one of the most powerful methods to determine surface structures. Analysis of LEED patterns and intensities provides the size and shape of the surface unit cell, the degree of order and detailed atomic structure with a precision of the order of picometers.

In LEED the electrons of kinetic energies between 10 eV and 150 eV are emitted from an electron gun impinging normal to the sample surface and - utilizing the high back scattering cross section - the backscattered electrons are filtered for suppression of the inelastically scattered electrons by a retarding field analyzer and after acceleration finally detected on a rear view fluorescent screen. The diffraction pattern represent the reciprocal space of the surface mesh of the unit cell, including reconstructions. It documents the long range ordering of the sample surface, rather than the local structure. If intensities are followed as a function of the electron energy (I-V analysis), relaxations and the base of the unit cell can be determined. Most frequent use is the assessment, if a sample surface or thin film is well prepared and has the correct orientation prior to further studies of the local or electronic structure.

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7448

Home-built (polarized/unpolarized) Raman spectrometer setup  

Metallic oxides can be a large share of the feedstock for processes of the petrochemical industry, electronic devices and optical components. Inside this class of materials, surfaces and interfaces are of particular interest, because they exhibit chemical and physical properties that distinguish them from their macroscopic pairs. Experimental and theoretical studies of gas-solid and liquid-solid interfaces demonstrate, in many instances, the importance of comprehending the reaction mechanisms between small molecules deposited over metallic oxides. Another effect that rises to the spotlight is the generation of new band occupation that might arise from the symmetry breaking in an interface between two solids. Generally, technics based in electron spectroscopy, like the XPS, UPS and the AES, can and should be applied in the first stages of a material’s characterization to determine the stoichiometry and to verify chemical modification of surfaces and interfaces. However certain aspects, like dopants present in very small concentration, can pose a challenge to these techniques, as they are hard to detect. In this search group, the use of an optical spectroscopy technic is proposed, based on the Raman effect, extracting important chemical and structural information of materials, even when there are only a small number of molecules or atoms being probed.

Raman spectroscopy of thin films  

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7488

 Home-built Nanopositing system

Nanopositioner by piezoelectric actuation, are electromechanical systems of space movement, these actuators allows the development of positioning systems of high resolution, in the micro-, nano- and sub-nanometric scale. As an ideal feature of operation the same need to have a fast response, high resolution of movement, stability, to ensure the correct stability and repeatability of the displacement, these devices have great appeal in scientific and industrial applications, such as probe microscopes, scanning electron microscopes, precision machining of parts and microelectronics. Although various models are already available in the market, they represent high cost components and generally have physical restrictions, in relation to their movement axes, dimensions and mass they can position. In this project it is proposed to elaborate a nanopositioner by actuation of shearplates with innovative design, that besides being able to position samples in 3 dimensions with high resolution can act in conditions of low temperature and ultra high vacuum.

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7488

Contact Angle

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7488

NAP XPS-FTIR

The combination of different analysis techniques allows for getting a deeper insight into the studied processes and Near Ambient Pressure X-ray Photoelectron Spectroscopy (NAP-XPS) delivers information about the chemical composition of the sample surface at a very high specificity.

 XPS spectra are obtained by illuminating the sample surface with monochromatic X-rays and measuring the energy of the photo-emitted electrons with an information depth of up to 10 nm for standard soft X-ray excitation sources. Thus, it provides qualitative and quantitative information about the elemental composition and the chemical state of the surface.

XPS analysis technique is used under ultra-high vacuum (UHV) conditions and this strongly restricts the type of samples that can be investigated mainly to solid samples or liquids with a very low vapor pressure. Therefore, model systems rather than real samples in their generic environments can be investigated by using standard XPS techniques in UHV.  With the NAP system the sample is surrounded by a gas atmosphere and no UHV conditions are required in the analysis area. Therefore, investigations of a large variety of different samples, including insulating samples, biological samples, gases, liquids and their interfaces are easily accessible. When measuring XPS in a gas atmosphere, the emitted photo-electrons from samples are scattered by collisions with surrounding gas molecules before entering the hemispherical electron analyzer.

IR-spectroscopy is also an established method for measuring the vibrational signature of a molecule. It can distinguish between molecules in the gas phase and adsorbed molecules on a surface on different sites. Therefore, FTIR technique is extremely well suited for investigations of surfaces under a specific gas atmosphere and a widely-used complementary investigation method to NAP-XPS.

FTIR 

Fourier-transform infrared spectroscopy (FTIR) is a technique used to observe molecular vibrational modes at  infrared spectrum., its very used to indentify functional groups, compounds, in the detection and characterization of thin films, monolayers and on surface analysis. FTIR spectroscopy enables scientists to measure trends and profiles of reactions in real time, providing highly specific information about the kinetics, mechanisms and pathways of reactions and the influence of reaction variables on performance.

In a minor example, IR spectral studies were performed using , DRIFTS and attenuated total reflectance (ATR) techniques to measure and investigate the vibrational bands present in starch powder and in gelatinized starch film after alkali treatments. In other analyses DRIFTS was performed to investigate hematite powder samples diluted to 10% by mass in a KBr matrix, to see changes visualized in the difference spectra by subtracting the bare hematite spectrum from the conditioned hematite one.  Font

The Vertex 70v Bruker FTIR in our lab are builded with new technologies that can have PEAK sensitivity in the mid-, near and far IR/THz regions without masking very weak spectral features caused by water vapor or CO2 absorptions and enhance results in the area of nano-science research down to sub-monolayers. Also, this offer possibility to operate in ultrahigh vacuum when assembling with the NAP-XPS.

Contact Information:  interfaces@cbpf.br

Phone Number Room: +55 (21) 2141 7488