Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Thin film morphology and electrical resistivity play an important role in modern technologies. In particular, subcomponents fabricated by Ti play an increasing role in microelectronic device technology as well as in the biomedical area [1-2]. Here the influence of substrate temperature (during deposition) and film thickness on the surface morphology and electrical resistivity of polycrystalline Ti and Zr thin films have been investigated.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

The possibility of analyzing surfaces at the nanoscale provided by atomic force microscopy [1] (AFM) has been explored for various materials, including polymers [2], biological materials [3] and clays [4]. Further uses of AFMs involved nanomanipulation [5] and measurements of interaction forces, where the latter has been referred to as atomic force spectroscopy (AFS) [6]. Measurements of surface-surface interactions at the nanoscale are important because many materials have their properties changed at this range [7]. For samples in air, the interactions with the tip are a superimposition of van der Waals, electrostatic and capillary forces. A number of surface features can now be monitored with AFS, such as adsorption processes and contamination from the environment. Many implications exist for soil sciences and other areas, because quantitative knowledge of particle adhesion is vital for understanding technological processes, including particle aggregation in mineral processing, quality of ceramics and adhesives. In this paper, we employ AFS to measure adhesion (pull-off force) between the AFM tip and two types of substrate. Adhesion maps are used to illustrate sample regions that had been contaminated with organic compounds.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

The incorporation of soft rubber into a thermoplastic matrix can lead to tough blends. Generally, such binary blends are immiscible and exhibit poor mechanical properties caused by the unfavorable interactions between the two phases. Thus, there is an enormous interest in polymer blend compatibility to improve the properties of the polymer blends by the addition of an appropriate compatibilizer [1,2].

The need of techniques for determining the mechanical properties of thin films, e.g. hardness coatings on ion beam treated surfaces has prompted a study of the microindentation hardness technique. The present interest is driven to a good understanding of the adhesion, friction, wear, and indentation processes. In most of the solid-solid interfaces of technological relevance, it occurs contact in many asperities, and this is why the study of fundamental properties of micro-mechanic and tribology of surfaces and interfaces is very important. The recent developments of different microscopic techniques based on tips and force surface devices (i.e. AFM, FM, LFM) allowed investigations of interfacial problems with high resolution and have led to the nanoscale regime the mechanical properties study for a wide spectrum of materials. In this work a method for Young's modulus determination of hard coatings multilayers of TiN/ZrN is evaluated. This method is based on AFM and spectroscopy-force modes [1-2].

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Molecular level organization has been a subject of great relevance in supramolecular chemistry and nanotechnology. Supramolecular chemists count on the ability of molecules to form several kinds of organization, allowing the development of nanoscaled devices. In this way, the scanning probe microscopy provides a great tool for characterization, manipulation and interfacing such devices [1]. Regarding the ruthenium complexes [Ru(bpy)2Cl(BPEB)](PF6) and {[Ru(bpy)2Cl]2(BPEB)}(PF6)2, where bpy = 2,2'-bipyridine, the presence of the BPEB (1,4-bis[4-pyridyl)ethenyl]benzene) ligand has an important role as a recognition site for van der Waals interactions (Figure 1). On the other hand, cyclodextrins are macrocyclic molecules bearing a hydrophobic cavity that can support several types of guest molecules [2-3]. In this work we are showing the influence of the recognition site of the BPEB ligand and the formation of an inclusion compound in the patterning structures of films deposited over mica substrates, by SFM microscopy.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Although the development of conducting polymers is very recent, such materials have already been shown to possess a number of useful properties that may be exploited in a range of technological applications. In particular, the representative conducting polymer polypyrrole (PPy) has been the subject of considerable research interest owing to its facile polymerisation and practical application in products as diverse as gas sensors [1], electrochromic devices [2] and battery / capacitor components [3].

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Cold rolled sheets of AISI 430 ferritic stainless steel have been widely used in kitchen utensils, ornamental articles, among other products due to their corrosion resistance and good formability. However, a localized increase of the surface roughness, known as ridging, develops during ferritic stainless steel forming [1]. The ridging is caused by anisotropic plastic flow of the material containing alternated bands of different crystallographic textures. These bands, or grain colonies, are formed during hot rolling fabrication step. During this step, the deformed grains can undergo dynamic recrystallization and/or recovery. In the regions where recovery takes place these texture bands are formed. In order to study ridging, it is necessary to identify the recovered regions (regions containing sub grains with nearly the same crystal orientation) and recrystallized regions (regions containing grains with different crystal orientations). Two well established techniques are applied to the characterization of recrystallized and recovered grains: the optical microscopy with polarized light, normally done in samples prepared with colored etching, and the electron backscatter diffraction (EBSD). In this work, atomic force microscopy (AFM) and magnetic force microscopy (MFM) were used to study the recrystallization and the recovery of the deformed specimens.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

In this study, the surface morphology of electrodeposited Ni on single crystal GaAs (001) was investigated by atomic force microscopy (AFM). The images show granular deposits with stepped contours typical of single-crystalline grains. The correlation length correlates very well with the size of the grains, indicating that the layers grow as columns with diameter increasing with thickness. This growth mechanism is observed for layers with thicknesses in the range of 10 to 500 nm at a deposition rate of ~0.5 nm/s.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

The controlled construction of nanostructures on solid surfaces for technological applications depends primarily on a deep understanding of the physical chemistry of the interface. Several methods have been devised to grow metallic nanostructures on solid surfaces, notably physical vapor deposition and electrodeposition. The electrochemical method led to the creation of a very promising technology called Electrochemical Step Edge Decoration (ESED) by the Penner group in Irvine, Ca. In this method, metallic nano and mesowires are built through electrochemical deposition on the step edges of the basal plane of Highly Oriented Pyrolytic Graphite (HOPG) [1]. The proposed growth mechanism is based on the Terrace-Ledge-Kink (TLK) model [2], in which the foreign adatoms nucleate the electrochemically induced growth of nanoparticles in the lower plane of step edges. White and collaborators [3], while studying the stability of gold nanoparticles electrodeposited on HOPG, noticed the preferential nucleation on the upper plane of step edges in stark opposition to the TLK model. They proposed that this preferential deposition is associated with a slippage of the atomic layer near the edge. This proposition indicates that the surface in the upper plane near the edge will present a decrease in the atomic distance in the plane, disrupting the registry with the underlying plane. To further assess this proposition we have devised another experimental approach where, instead of electrodepositing foreign adatoms for nucleation and growth, we deposited fully formed silver nanoparticles on HOPG through a Self Assembly mechanism and studied its spatial distribution. Through this approach, we intend to study the surface mobility of nanoparticles, as opposed to atomic species as studied in electrochemical deposition.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005

Surface chemistry and topography of materials are generally preponderant factors in a series of material properties, such as adhesion, wettability, friction and optical properties [1]. Wettability of films, for example, can be altered significantly by modifying its surface roughness and also by incorporating functional groups. Plasma treatment is a powerful and versatile way to modify surface properties of amorphous nitrogen-incorporated carbon thin films (a-C:H(N)) and obtain materials with improved properties, once it is possible to modify the surfaces in a controlled way by specific settings of plasma conditions. [2 - 4]