Nano scale research relies on fabricating materials and devices, constructing devices and systems from them, and characterizing their properties as well as the performance parameters for which they are designed, with impacts on both science and technology applications. While this picture is not fundamentally different from that of earlier generations of materials-based science and technology, progress in nano science and engineering is gated by striking challenges in all these areas. Indeed, in many cases these can be regarded as "grand challenges", in the spirit of those underscored by the National Nanotechnology Initiative (e.g., nanoscale instrumentation and metrology, manufacturing at the nanoscale, or nanostructured materials by design).

Maryland NanoCenter is directly addressing the profound challenges which distinguish the nano era from its predecessors, with leadership roles and major advances in areas such as scanning nanoprobe techniques to reveal properties and behavior on an atomic and nano length scale, generation of highly controlled and chemically tailored nanoparticles for catalysis and other applications, development of molecular electronic devices and their assembly into useful circuits, and biomolecular engineering carried out in microscale fluidic systems.

Components

Maryland NanoCenter is pursuing a broad range of nano research which covers four key components - fabrication, characterization, systems, and performance.

fabrication

Design and fabrication of molecules, materials, and nanostructures at the nano scale represents an enormous hurdle and challenge to nano researchers. The synthesis of nanostructured materials with novel properties requires substantial insight into controlling physical and chemical mechanisms, as well as macro-scale equipment suitable to control process conditions sufficiently during synthesis. Where artificial nanocomponents are involved (e.g., nanotubes, nanoparticles), novel processes must be used to synthesize them, and then these tiny objects must be assembled, contacted, or interrogated in order to reveal their behavior and properties, and to control their use. Even where naturally occurring entities are the subject (e.g., biomolecules), their chemical and structural complexity make it difficult to arrange them in ways which serve new functions. Many nanotechnology applications will demand the construction of more complex nano-based systems (e.g., molecular electronic circuits, as opposed to individual devices), and assembling these presents a yet higher level of complexity and control.

Maryland NanoCenter researchers bring to this challenge special strengths in areas such as templated self-assembly, nanotube and quantum device fabrication, nanoparticle synthesis, cell manipulation, focused ion beam nanofabrication, biomolecular design, thin film functional and smart materials, nanostructured polymer systems, and nano-scale control in materials processing.

characterization

The partner to fabrication is characterization, namely the observation and quantification of properties and behavior of nanomaterials, nanocomponents, and nanosystems. Such characterization is clearly challenged not simply by the small length scales involved in nano, but specifically by the need to apply multiple nanocharacterization techniques that elucidate various aspects of properties and behavior (e.g. chemistry, composition, and structure), together with performance metrics (e.g., electrical, thermal, mechanical,magnetic). Understanding of nano scale phenomena requires correlation of such characteristics and their relation to fabrication and synthesis parameters.

Major advances in nanoscale characterization have a long tradition at UMD, particularly in scanning probe techniques ranging from scanning tunneling microscopy and atomic force microscopy to microwave and magnetic field scanning probes and near-field optics. Focused electron, ion, and photon beams also provide for nanocharacterization from structural and chemical contrast. And time-resolved methods (e.g., picosecond and femtosecond spectroscopies) hold promise for new pathways to understanding properties and phenomena at the nanoscale.

systems

Though it may be less obvious, systems behavior will be important - perhaps even more important - at the nanoscale than in more conventional domains of science and technology. One striking example is nanomanufacturing, the venue by which commercial applications of nano are probably most anticipated. Whether in the context of migrating manufacturing equipment and processes to fabricate at the nanoscale or in revolutionary approaches to building nanosystems using self-assembly, the intrinsic issues of manufacturing are present: operations sequencing, tolerances and yield consequences of statistical variability, process metrology and control, modeling and optimization, cost-performance tradeoffs, etc. At the other extreme, fundamental understanding of biomolecular reactions is an equally systems-based challenge, in which complex sequences of natural biochemical reaction steps determine how living systems are self-regulating. Disentangling these biochemical pathways and kinetics offers the chance to understand the essential biology and to develop applications in medicine and chem-bio detection based on modifying and controlling these pathways.

Maryland NanoCenter researchers are directly addressing nanomanufacturing and nanosystems issues in areas such as metabolic pathways involving proteins, biomedical lab-on-chip, and assembly of systems from nanocomponents. In addition, they maintain ongoing interaction with systems-oriented UMD researchers who have expertise in systems areas such complex operation sequences and planning, modeling and simulation, optimization, and control.

performance

When aimed at nanotechnology applications, nano materials, structures and systems are explored in order to achieve particular performance metrics (e.g., specific electrical, magnetic, or mechanical properties). Characterizing relevant metrics can require the fabrication of test sites at a micro- or nano- scale level, since it is in such structures that nano materials and devices are to be used. In this regard, progress can be gated by the extent to which the research elucidates relationships between synthesis, characterization, and performance properties. The situation is analogous to the traditional mantra of materials science - advances come from process-structure-property relationships.

A number of research programs in Maryland NanoCenter have placed strong focus on rigorous determination of performance metrics in order to enable both applications and fundamental knowledge. Examples include scanning microprobe measurements of magnetization and high frequency dielectric behavior in complex multicomponent functional materials, tribological testing of materials, determination of conversion efficiency in chemical and biochemical reactions, and cycle-testing of nominally reversible biomolecular reactions.

Applications

Nano scale research with focus on fabrication, characterization, systems, and performance promises major impact in pioneering and profound advances in fundamental science and in a broad array of pervasive applications. See Nano's impact for further perspective.

fundamental science

Nano research has tremendous potential to deliver pioneering advances in fundamental science. By identifying properties and behavior at nano length scales as well as employing components which intrinsically exist at these small scales, fundamental physical and chemical behavior may be more accessible to research. Furthermore, novel phenomena directly associated with the nanoscale dimensions can be investigated. And nanosystems fabricated and assembled for applications may turn to unique laboratories for revealing fundamental science: e.g., a lab-on-chip for medical testing in a clinic may also function as an outstanding research laboratory for unraveling biomolecular reaction pathways.

technology & products

Nanotechnology applications can be envisioned across many fields, including information technology, biomedicine, defense and security, energy and environment, and consumer products. It seemss likely that early applications will be through systems where nanotechnology provides an enhancement, without a revolutionary change in overall design and manufacturing. In the longer term, one can certainly anticipate that nano will bring truly revolutionary concepts, designs, and strategies for manufacturing systems, along with profound advances in fundamental knowledge.