27 Oct 2009
Meyya Meyyappan of the NASA Ames Research Center picks out some of his favourite papers from Nanotechnology as the journal celebrates its 20th volume
This year marks the 20th volume of Nanotechnology, the first journal dedicated to the emerging field of nanoscale science and technology, pre-empting the US National Nanotechnology Initiative (NNI) by ten years.
Throughout the evolution and revolution of nanomaterials and devices, Nanotechnology has been at the forefront. The journal's first article on nanoelectronics reported research on electronic transport through three-dimensionally confined semiconductor quantum dots by Prof. Mark Reed, now editor-in-chief, and his colleagues at the time at Texas Instruments in Dallas (Reed M A, Randall J N and Luscombe J H 1990 Nanotechnology 1 63–6).
In the first decade of the journal, papers on nanoelectronics were scarce and primarily reported research on resonant tunnelling devices, transport in quantum dots and other III-V devices. With the ability to produce single-walled carbon nanotubes (SWCNTs) and semiconducting nanowires on patterned substrates using CVD and similar techniques, nanoscale electronics and photonics flourished. A pioneering contribution by Collins et al (Collins P G, Bando H and Zettl A 1998 Nanotechnology 9 153–7) discussed conductivity measurements on SWCNTs using scanning tunnelling microscopy. In the same issue, Fritzsche et al (Fritzsche W, Böhm Unger E and Köhler J M 1998 Nanotechnology 9 177–3) discussed making electrical contacts to a single molecule, another early contribution in molecular electronics.
There have been numerous interesting and trend-setting articles. My personal favourite is an article from Hewlett-Packard researchers Greg Snider, Phil Kuekes and Stan Williams (2004 Nanotechnology 15 881–91) discussing an approach to building a defect-tolerant computer out of defective configurable FETs and switches. The construction of defect-free materials, devices and components may well begin to pose an obstacle to nanotechnology, so this pioneering article exhibits extraordinary foresight in attempting to construct a useful machine from defective parts.
The field of optoelectronics and photonics has been benefiting from the ability to synthesize semiconducting nanowires and quantum dots. Advances in light-emitting diodes, photodetectors, nanolasers, solar cells, and field emission devices have been abundantly reported in the journal. The future of these devices depends on our ability to control the size, orientation and properties of one- and zero-dimensional materials.
The forecast for electronics and photonics has vastly underestimated developments, with predictions such as "future computers will weigh no less than 1.5 tons". Over the past 20 years, the number of transistors on a chip has risen from just 1 million to 2 billion, and is still increasing. Now the biggest question is: what will take over from Moore's law in about a decade? This question has been driving the research agenda in electronics across the industrial and academic world.
The first answer appears to be integrating other functional components with logic and memory such as miniature camera modules, GPS, accelerometers, biometric identification, health monitoring systems, etc. Such integration is actively being pursued by industry.
In contrast, a lot of new research is still driven by material innovations, for example, carbon nanotube based electronics. Rudimentary devices and circuits using SWCNTs have been demonstrated to outperform silicon devices of comparable size. However, controlling the chirality and diameter of SWCNTs is still a problem, as is the manufacture of 300–400 mm wafers with over 5–10 billion transistors, and all of this assumes that continuing on the path of CMOS but using a different material is the right approach in the first place. In the meantime, silicon and germanium in the form of nanowires may make their way into electronics. Then there is molecular electronics where conducting organic molecules could now become the heart of electronic components, although the precision and controllability of electrical contact with molecules remain challenging.
The journal Nanotechnology has grown with the field, from a modest four issues per year for several years to what is now a weekly publication with a dedicated section to electronics and photonics. We look forward to more and more of your highest-quality papers (to find out how you can submit your paper to Nanotechnology, click here).
Popular papers from 2009
To browse the 20th volume special issue in full, click here.