Editorial Feature

Tools and Fabrication in Bottom-up Manufacturing for Nanotechnology

Article updated on 15 January 2020.

Tools and Fabrication in Bottom-up Manufacturing for Nanotechnology

The tools here support futuristic approaches to nanotechnology manufacture based on bottom-up approaches, such as nanomachine production lines. This approach is equivalent to building a car engine up from individual components, rather than the less intuitive method of machining a system down from large blocks of material.

Indeed, although such techniques are still in their infancy, there has been a recent move away from top-down techniques towards bottom-up manufacturing within the international research community, as reported by the UK Department for Innovation, Universities, and Skills (formerly DIT). Scientists and engineers are becoming increasingly able to understand, intervene and rearrange the atomic and molecular structure of matter, and control its form to achieve specific aims.

Self-assembly and self-organization

Self-assembly refers to the tendency of some materials to organize themselves into ordered arrays. This technique potentially offers huge economies and is considered to have great potential in nanoelectronics. In particular, the study of the self-assembly nature of molecules is proving to be the foundation of rapid growth in applications in science and technology. For example, Ottilia Saxl reports that the Stranski–Krastonov methods for growing self-assembled quantum dots have rendered the lithographic approach to semiconductor quantum dot fabrication virtually obsolete.

Creating new nanocomposites with organic molecules

Furthermore, self-assembly is leading to the fabrication of new materials and devices. New materials include new types of nanocomposites or organic/inorganic hybrid structures that are created by depositing or attaching organic molecules to ultra-small particles or ultra-thin man-made layered structures.

Organic films and solid-state chips

Similarly, new devices range from the production of new chemical and gas sensors, optical sensors, solar panels, and other energy conversion devices, to bioimplants and in vivo monitoring. The basis of these technologies is an organic film (the responsive layer) which can be deposited onto a hard, active electronic chip substrate. The solid-state chip receives signals from the organic over-layer as it reacts to changes in its environment and processes them. The applications for these new materials and devices are summarized in Table 1.

Table 1. Applications for new materials and devices resulting from self-assembly and self-organization.

Name

Technique

Applications

New materials

Sol-gel technology

Combining inorganic and organic components

The design of different types of materials; functional coatings

Intercalation of polymers

Intercalating polymers with other materials (DNA, drugs)

Toxicity testing; drug delivery; drug performance analysis

Nano-emulsions

Selecting nano-particle size and composition

Production of required viscosity and absorption characteristics

Biometrics

Design of systems and materials and to mimic nature’s functionality

Biosensing; optical switching

New devices

Field-sensing devices

Combination of molecular films with optical waveguides and resonators

Biosensing; optical switching

Material-sensing devices

Surfaces of liquid crystals or thin membranes and other organic compounds used to detect molecules via structural or conductive changes

Gas and chemical sensing

Software modeling to simulate molecular structures

Molecular modeling software is another fabrication technique of wide-ranging applicability as it permits the efficient analysis of large molecular structures and substrates. Hence, it is much used by molecular nanotechnologists, where computers can simulate the behavior of matter at the atomic and molecular levels.

Also, computer modeling is proving essential to our understanding of nanoscale structures that operate at the mesoscale, an area where both classical and quantum physics influence behavior.

Nanometrology

Fundamental to commercial nanotechnology is repeatability, and fundamental to repeatability is measurement. Nanometrology measures physical dimensions at the nanometer and subnanometer levels. This is essential if the highly specialized applications of nanotechnology are to operate correctly, such as X-ray optical components and mirrors used in laser technologies.

Primary author: Alexander Huw Arnall.

Source:

Greenpeace. Future Technologies, Today’s Choices Nanotechnology, Artificial Intelligence, and Robotics; A technical, political and institutional map of emerging technologies. July 2003.

For more information on this source please visit Greenpeace.

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