Multi-flavoured nanowires can act as miniature bar-codes, diodes and light sources
Wires one-millionth of a millimetre wide change composition along their length.
Wires one-millionth of a millimetre wide that change chemical composition along their length, just as fruit pastilles change flavour along a packet, have been grown in the United States. These multi-flavoured nanowires can act as miniature bar-codes, diodes and light sources.
Conventional microelectronics components are etched into flat layers of semiconducting material. Charles Lieber and colleagues at Harvard University in Cambridge, Massachusetts, grow their wires - smaller than the thinnest wire on a commercial silicon chip - from vapours of the atomic ingredients.
Superlattice lines up
The team has made wires about 20 nanometres across that contain alternating sections of the semiconductors gallium arsenide and gallium phosphide. Microelectronic engineers often use structures like this, called superlattices, in electronic devices. They are currently made by carving up flat sandwiches of layered semiconductors.
Superlattices are used, for example, as mirrors in microscopic lasers, or as waveguides to capture and confine light. If electrons are trapped in a thin layer of a semiconductor sandwiched between barriers of a different semiconductor, quantum wells are created that emit light. The colour of the light can be tuned by varying the well thickness.
Nanowire superlattices could be used in all these applications. Their size means that many more could be packed onto a single chip than today’s microelectronics components. The researchers envisage making nanowire lasers, for example.
Up the junction
To demonstrate the wires’ potential, Lieber’s group made structures called p-n junctions. They grew silicon nanowires in two sections, each spiced with a different additive to fine-tune the electrical behaviour of the silicon. These nanowire p-n junctions behave like diodes - they let current flow in only one direction.
The team also made p-n junctions that act as light-emitting diodes. Because these glowing devices are so small, the researchers hope to make them expel light one photon at a time. This could be useful in a new type of ultra-powerful information processing called quantum computing.
PHILIP BALL | © Nature News Service
Japanese researchers develop ultrathin, highly elastic skin display
19.02.2018 | University of Tokyo
Why bees soared and slime flopped as inspirations for systems engineering
19.02.2018 | Georgia Institute of Technology
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
19.02.2018 | Materials Sciences
19.02.2018 | Materials Sciences
19.02.2018 | Life Sciences