Nanoscience and Nanotechnology

Atomic Force Microscope Nanolithography on Organized Molecular Films Part 2 (Nanotechnology)

Anodization AFM nanolithography on self-assembled monolayers (SAMs) Achieving fast lithographic scan speed is an important task to apply AFM to electronic devices. Because organic resist on silicon substrate can affect to the lithographic speed, it raises considerable interest in AFM anodiza-tion lithography. In the case of AFM anodization, the electronic feature of terminal group of […]

Atomic Force Microscopy and Single-Molecule Force Microscopy Studies of Biopolymers Part 1 (Nanotechnology)

INTRODUCTION Biopolymers are macromolecules of biological origin, which include nucleic acids (DNA and RNA), proteins, peptides, and polysaccharides. Although these macro-molecules influence biological processes in different ways, most biological processes are associated to some extent with the physical properties of biopolymers (chain structure, flexibility, and excluded volume interactions). For example, the conformation of bacterial surface […]

Atomic Force Microscopy and Single-Molecule Force Microscopy Studies of Biopolymers Part 2 (Nanotechnology)

Folding and Unfolding of Proteins Proteins are molecules that are composed of a sequence of amino acids. This sequence of amino acids determines the complex helical shape that the protein will assume. The protein helix can be denatured under special conditions (chemical or thermal) and refold to its native state upon the removal of the […]

Atomic Force Microscopy Imaging and Force Spectroscopy of Microbial Cell Surfaces Part 1 (Nanotechnology)

INTRODUCTION Characterization of the structural and physical properties of microbial cell surfaces is a continuously expanding field of microbiology.[1-10] Studying cell surfaces is important not only in basic research to elucidate their functions (cell shape, protection, molecular sieve, molecular recognition, cell adhesion, and cell aggregation), but also in medicine (fouling of implants, microbial infections) and […]

Atomic Force Microscopy Imaging and Force Spectroscopy of Microbial Cell Surfaces Part 2 (Nanotechnology)

Spatially Resolved Force Spectroscopy The microbial surface is rarely of homogeneous composition, but is rather made of a complex mixture of macro-molecules. As a result, a single cell can show important lateral variations of physical properties. Until recently, such local variations of properties were very difficult to measure, especially on hydrated, living cells. With spatially […]

Atomic Force Microscopy Imaging Artifacts Part 1 (Nanotechnology)

INTRODUCTION The invention of the atomic force microscope (AFM; also known as scanning probe microscope, SPM) in 1986[1] has revolutionized the way researchers study surfaces.[2] Material surfaces such as metallic or polymeric thin films can be imaged under ambient conditions (air, liquids) with nanometer resolution. Furthermore, it is now possible to image biological species such […]

Atomic Force Microscopy Imaging Artifacts Part 2 (Nanotechnology)

CHANGING SURFACE STRUCTURES DURING IMAGING Unlike optical microscopy or electron microscopy, atomic force microscopy uses physical force to image the surface ”by feel” and not by electromagnetic radiation or electrons. This mechanical force can often be destructive to the surface itself. Lateral forces because of the rastering of the tip over the surface can cause […]

Atomic Force Microscopy Simulation of Interaction Forces in CMP Applications Part 1 (Nanotechnology)

INTRODUCTION Chemical mechanical polishing (CMP), otherwise known as chemical mechanical planarization, has been an enabling catalyst for rapid technological advancements in microelectronic fabrication and design over the last decade. Although now a multibillion-dollar business in the microelectronics industry, besides patents, there is a dearth of scientific publications on the subject. After initially touching on the […]

Atomic Force Microscopy Simulation of Interaction Forces in CMP Applications Part 2 (Nanotechnology)

Particle-Substrate Interactions Although particle-particle interaction can be simulated by AFM to ensure adequate slurry stability—which translates into lower surface defectivity and fewer wafers lost to large-scale surface deformations (scratches)—particle-surface interactions drive the material removal and planarization processes. Hence the overall effectiveness of the CMP process largely depends on these interactions. Not surprisingly, the majority of […]

Atomic Force Microscopy Simulation of Interaction Forces in CMP Applications Part 3 (Nanotechnology)

Pull-Off Force Measurements—Deciphering Dispersant Molecule Adhesion Mechanisms To design surfactant-dispersed slurries with appreciable polishing rates, the dominant mechanism leading to the presence of residual monomer at the solid-liquid interface needed to be determined. Pull-off force measurements— the force required to detach the colloidal probe from the planar substrate—were performed in an attempt to gain additional […]

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