The commercial realization of carbon nanotube-based electronic devices and their integration into the existing silicon-based processor technologies is still hampered by the inability to scale up the - currently lab-based - fabrication processes to manufacture a large number of devices on a single chip. The fundamental issue of carbon nanotube device fabrication still remains the biggest challenge for effective commercialization of nanotube electronics. In a further step towards large-scale integration of single-walled carbon nanotubes (SWCNTs) into complex functional electronic circuits, researchers have now combined a previously developed dielectrophoretic deposition approach with SWCNT sorting using density gradient ultracentrifugation, ensuring high purity of SWCNTs in suspension and consequently in the assembled devices.
Although organic semiconductor materials cannot yet be packed as densely as state-of-the-art silicon chips, they require less power, cost less and do things silicon devices cannot: bend and fold, for example. Once perfected, organic semiconductors will permit the construction of low-cost, spray-on solar cells and even spray-on video displays. Notwithstanding tremendous progress in the area of organic electronics, several major challenges still exist. To address these challenges, researchers have combined organic electronics with nanoelectronics and developed the first 2D crystal of organic semiconductors on the millimeter scale, the thickness of which is only a single molecular layer, but with perfect long-ranged crystalline order.
Printed electronics has its origins in conductive patterns printed as part of conventional electronics, forming flexible keyboards, antennas and so on. Then came fully printed testers on batteries, electronic skin patches and other devices made entirely by printing, including batteries and displays. A clear next step has been to modernise static print with the e-reader and the talking poster with animated, light emitting display and solar power. These are partly or almost wholly printed, with a clear roadmap to making them lower cost and more reliable and flexible by using printing more fully in their manufacture in future. However, we now see printed electronics and electrics certain to penetrate far more applications than anyone realised.
One of the many fascinating concepts in nanotechnology is the vision of molecular electronics where researchers are investigating nanostructured materials to build electronics from individual molecules. If realized, the shift in size from even the most densely packed computer chip today would be staggering. Molecular electronics aims at the fundamental understanding of charge transport through molecules and is motivated by the vision of molecular circuits to enable miniscule, powerful and energy efficient computers. A research team in Germany has now demonstrated that rigidly wired molecules can emit light under voltage bias. This result is important for fundamental science but it also adds to the molecular electronics vision an optoelectronic component, i.e. the development of optoelectronic components on the basis of single molecules.
So far, there have been no research reports on a graphene-based transistor amplifier and investigations of its in-field controllability for analog, mixed-signal, and radio-frequency applications. Previous work on graphene transistors has largely focused on frequency multiplication near the Dirac point in graphene current-voltage characteristic. But now, a team of researchers has demonstrated the first triple-mode graphene amplifier. They have shown experimentally that by leveraging the ambipolarity of charge transport in graphene, the amplifier can be configured in the common-source, common-drain, or frequency multiplication mode of operation by changing the gate bias. This is the first demonstration of a single-transistor amplifier that can be tuned between different modes of operation using a single three-terminal transistor. Moreover, during its operation, the graphene amplifier was configured in-field to switch between the different modes. The result marks another important step toward graphene applications in electronics.
Zinc oxide is considered a workhorse of technological development exhibiting excellent electrical, optical, and chemical properties with a broad range of applications as semiconductors, in optical devices, piezoelectric devices, surface acoustic wave devices, sensors, transparent electrodes, solar cells, antibacterial activity etc. Thin films or nanoscale coating of ZnO nanoparticles are viewed with great interest for their many potential applications as substrates for functional coatings. Researchers in Taiwan have now shown, for the first time, that they can directly grow vertically aligned, highly crystalline and defect-free single-crystalline zinc oxide nanorods and nanoneedles on paper.
As technology keeps getting faster and smaller, the computer industry is working towards the end of the Moore's Law roadmap where technology will eventually be designed and created at the atomic level. Rather than working their way down incrementally, some researchers are taking a different approach by exploring what happens at the end of Moore's Law, specifically whether it is possible to do computing and other work at that scale. This means they are asking questions like, 'how many atoms are needed to store information', and 'are there schemes to do computation with magnetic atoms instead of transistors'? An IBM research team has now demonstrated, for the first time, the ability to measure how long an individual iron atom can hold magnetic information. They show how a scanning tunneling microscope can measure electron spin relaxation times of individual atoms adsorbed on a surface with nanosecond time resolution using an all-electronic pump-probe measurement scheme.
Electron pumps are devices that can transfer a certain number of electrons during each pumping cycle. Besides being of fundamental interest to physicists, single-electron pumps have a potential for practical application in metrology, acting as an accurate frequency-current converter. The general goal of this field is to build a current standard based on the electrical charge of a single electron in order to achieve high accuracy for current measurement. A device called single-electron transistor (SET) can confine charges down to single electron level and hence is applicable for quantized current generation. Attempts to generate quantized current in nanotubes have been made with various methods over the past few years, but were not very successful in obtaining a high degree of current quantization. A research team in Germany has now demonstrated the feasibility of using a single molecule - in this case, a single-walled carbon nanotube - for the generation of quantized electric current.