Portal:Nanotechnology

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Welcome to the nanotechnology portal

Nanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometers.

Nanotechnology is very diverse, including extensions of conventional device physics, new approaches based on molecular self-assembly, developing new materials with nanoscale dimensions, and investigating whether we can directly control matter on the atomic scale. Nanotechnology entails the application of fields as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, microfabrication, etc.

There is much debate on the future implications of nanotechnology. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biomaterials and energy production. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on global economics, as well as speculation about various doomsday scenarios.

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Self-assembled monolayer schematic

Self-assembled monolayer

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A self-assembled monolayer (SAM) is an organized layer of amphiphilic molecules in which one end of the molecule, the "head group" shows a specific, reversible affinity for a substrate. SAMs also consist of a tail with a functional group at the terminal end. SAMs are created by the chemisorption of hydrophilic head groups onto a substrate from either the vapor or liquid phase followed by a slow two-dimensional organization of hydrophobic tail groups. Initially, adsorbate molecules form either a disordered mass of molecules or form a "lying down phase", and over a period of minutes to hours, begin to form crystalline or semicrystalline structures on the substrate surface. Areas of close-packed molecules nucleate and grow until the surface of the substrate is covered in a single monolayer.

Selecting the type of head group depends on the application of the SAM. Typically, head groups are connected to an alkyl chain in which the terminal end can be functionalized (i.e. adding –OH, –NH3, or –COOH groups) to vary the wetting and interfacial properties. Substrates can be planar surfaces, such as silicon and metals, or curved surfaces, such as nanoparticles. Alkanethiols are the most commonly used molecules for SAMs. They are used on noble metal substrates because of the strong affinity of sulfur for these metals. Silanes are generally used on nonmetallic oxide surfaces. Metal substrates for use in SAMs can be produced through physical vapor deposition techniques, electrodeposition or electroless deposition.

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Quantum corral

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Image of an elliptical quantum corral built using the autonomous atom assembler; cobalt atoms were deposited at sub-monolayer coverage on a Cu(111) at 7K in ultra-high vacuum and subsequent scanning tunneling microscope measurements were performed at a 4.3 K sample temperature.
Credit: Joseph A. Stroscio, Robert J. Celotta, Steven R. Blankenship, and Frank M. Hess/NIST

Image of an elliptical quantum corral built using the autonomous atom assembler; Cobalt atoms were deposited at sub-monolayer coverage on a Cu(111) at 7K in ultra-high vacuum and subsequent scanning tunneling microscope measurements were performed at a 4.3 K sample temperature.

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Nadrian Seeman in 2002

Nadrian Seeman

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Nadrian C. Seeman is an American chemist known as the founder of the field of DNA nanotechnology beginning in the early 1980s. Seeman's laboratory published the synthesis of the first three-dimensional nanoscale object, a cube made of DNA, in 1991, and the concepts of DNA nanotechnology later found further applications in DNA computing, DNA nanorobotics, and self-assembly of nanoelectronics. Seeman won the 1995 Feynman Prize in Nanotechnology "for developing ways to construct three-dimensional structures, including cubes and more complex polyhedra, from synthesized DNA molecules" and shared the 2010 Kavli Prize in Nanoscience for "development of unprecedented methods to control matter on the nanoscale".

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