#Scientists craft atomically seamless thinnest-possible semiconductor junctions Scientists have developed what they believe is the thinnest-possible semiconductor,
a new class of nanoscale materials made in sheets only three atoms thick. The University of Washington researchers have demonstrated that two of these single-layer semiconductor materials can be connected in an atomically seamless fashion known as a heterojunction.
This result could be the basis for next-generation flexible and transparent computing, better light-emitting diodes,
or LEDS, and solar technologies.""Heterojunctions are fundamental elements of electronic and photonic devices, "said senior author Xiaodong Xu, a UW assistant professor of materials science and engineering and of physics."
"Our experimental demonstration of such junctions between two-dimensional materials should enable new kinds of transistors, LEDS, nanolasers,
and solar cells to be developed for highly integrated electronic and optical circuits within a single atomic plane."
The researchers discovered that two flat semiconductor materials can be connected edge-to-edge with crystalline perfection.
which was key to creating the composite two-dimensional semiconductor. Collaborators from the electron microscopy center at the University of Warwick in England found that all the atoms in both materials formed a single honeycomb lattice structure, without any distortions or discontinuities.
thinnest-possible semiconductor junctions A high-resolution scanning transmission electron microscopy (STEM) image shows the lattice structure of the heterojunctions in atomic precision.
"Scientists craft atomically seamless, thinnest-possible semiconductor junctions With a larger furnace, it would be possible to mass-produce sheets of these semiconductor heterostructures,
the researchers said. On a small scale, it takes about five minutes to grow the crystals, with up to two hours of heating and cooling time."
"In the future, combinations of two-dimensional materials may be integrated together in this way to form all kinds of interesting electronic structures such as in-plane quantum wells and quantum wires, superlattices, fully functioning transistors,
and even complete electronic circuits.""The researchers have demonstrated already that the junction interacts with light much more strongly than the rest of the monolayer,
Researchers demonstrate ultrafast charge transfer in new family of 2-D semiconductors A new argument has just been added to the growing case for graphene being bumped off its pedestal as the next big thing in the high-tech world by the two-dimensional semiconductors
our study suggests that MX2 heterostructures, with their remarkable electrical and optical properties and the rapid development of large-area synthesis, hold great promise for future photonic and optoelectronic applications."
These 2d semiconductors feature the same hexagonal"honeycombed"structure as graphene and superfast electrical conductance,
but, unlike graphene, they have natural energy bandgaps. This facilitates their application in transistors and other electronic devices because
unlike graphene, their electrical conductance can be switched off.""Combining different MX2 layers together allows one to control their physical properties,
"For example, the combination of Mos2 and WS2 forms a type-II semiconductor that enables fast charge separation.
not only for photonics and optoelectronics, but also for photovoltaics.""MX2 semiconductors have extremely strong optical absorption properties
and compared with organic photovoltaic materials, have a crystalline structure and better electrical transport properties,
and MX2 semiconductors provide an ideal way to spatially separate electrons and holes for electrical collection and utilization."
#Conductive nanofiber networks for flexible unbreakable and transparent electrodes Transparent conductors are required as electrodes in optoelectronic devices, such as touch panel screens, liquid crystal displays, and solar cells.
However, ITO-based transparent electrodes are brittle, prone to breakage, and expensive. Therefore, there is strong demand for alternatives to ITO transparent electrodes.
Tokyo Institute of technology researchers report the first development of a facile method for the fabrication of flexible and unbreakable transparent electrodes using nanofibers.
Two-dimensional aluminum (Al) nanofiber networks offering transparent conductors were fabricated by simple wet chemical etching of Al metalized polymer films using an electrospun polystyrene nanofiber mask template.
and transparent electrodes are promising for applications in both large-scale and mobile optoelectronic devices including ones that are flexible.
Examples of applications are large displays, large interactive touch screens, photovoltaic solar panels, light-emitting diode panels, smart phones,
It uses an aluminum grating that can be added to silicon photodetectors with the silicon microchip industry's mainstay technology complementary metal-oxide semiconductor or CMOS.
This color filtering is done commonly using off-chip dielectric or dye color filters which degrade under exposure to sunlight
and can also be difficult to align with imaging sensors. Today's color filtering mechanisms often involve materials that are not CMOS-compatible
but this new approach has advantages beyond on-chip integration said LANP Director Naomi Halas the lead scientist on the study.
Bob has created a biomimetic detector that emulates what we are hypothesizing the squid skin'sees'Halas said.
Not only are we using the photodetector as an amplifier we're also using the plasmonic color filter as a way to increase the amount of light that goes into the detector he said.
To the best of the researchers'knowledge, this reversible capacity is the highest among all Co3o4 electrodes ever reported.
With these advantages, the researchers expect the df-G to bring significant advances of composite electrodes for a variety of electrochemical system,
and capacitors r
#Copper shines as flexible conductor Bend them, stretch them, twist them, fold them: modern materials that are light,
"A low loading of nano wires would be appropriate for a pressure sensor whereas a high loading is suitable for a stretchable conductor."
and for flexible displays and touch screens. They can be used in rubberlike electronic devices that, unlike paperlike electronic devices, can stretch as well as bend.
They can also be attached to topologically complex curved surfaces, serving as real skin-like sensing devices,
Associate professor Cheng said. In their report, published recently in ACS Nano, the researchers noted that devices using their copper-based aerogels were not quite as sensitive as those using gold nanowires,
In addition to providing multiple colors, multiplexing two nanoparticles has the advantage of increasing the bandwidth information limits.
#Graphene rubber bands could stretch limits of current healthcare New research published today in the journal ACS Nano identifies a new type of sensor that can monitor body movements
Although body motion sensors already exist in different forms they have not been used widely due to their complexity and cost of production.
Now researchers from the University of Surrey and Trinity college Dublin have treated for the first time common elastic bands with graphene to create a flexible sensor that is sensitive enough for medical use
-which imparts an electromechanical response on movement the team discovered that the material can be used as a sensor to measure a patient's breathing heart rate
Until now no such sensor has been produced that meets needs and that can be made easily. It sounds like a simple concept
and joint movement and could be used to create lightweight sensor suits for vulnerable patients such as premature babies making it possible to remotely monitor their subtle movements and alert a doctor to any worrying behaviours.
These sensors are compared extraordinarily cheap to existing technologies. Each device would probably cost pennies instead of pounds making it ideal technology for use in developing countries where there are not enough medically trained staff to effectively monitor
New sensor could light the way forward in low-cost medical imagin g
#Bacterial nanowires: Not what we thought they were For the past 10 years scientists have been fascinated by a type of electric bacteria that shoots out long tendrils like electric wires using them to power themselves
In addition this research has the potential to inform the creation of living microbial circuits forming the foundation of hybrid biological-synthetic electronic devices.
and others at the University of Massachusetts Amherst today report a breakthrough technique for controlling molecular assembly of nanoparticles over multiple length scales that should allow faster cheaper more ecologically friendly manufacture of organic photovoltaics and other electronic devices.
The new method should reduce the time nano manufacturing firms spend in trial-and-error searches for materials to make electronic devices such as solar cells organic transistors and organic light-emitting diodes.
Beyond catalysis, Ying predicts these new materials could be useful in electronics, chemical sensing and even biomedicine.
#An inkjet-printed field-effect transistor for label-free biosensing Thin-film transistors (TFTS) are powerful devices in semiconductor manufacturing
and form the basis of countless electronic devices such as memory chips photovoltaic cells logic gates and sensors. An interesting alternative to inorganic TFTS (silicon) is organic TFTS (OTFTS)
The Group published in the last issue of Advanced Functional Materials an article describing a flexible biological field-effect transistor (Biofet) for use in biosensing.
It was made by inkjet printing of an organic field-effect transistor (OFET) and subsequent functionalization of the insulator with specific antibodies.
An Inkjet-Printed Field-Effect Transistor for Label-Free Biosensing. Advanced Functional Materials. Article first published online:
#New graphene framework bridges gap between traditional capacitors batteries Researchers at the California Nanosystems Institute (CNSI) at UCLA have set the stage for a watershed in mobile energy storage by using a special graphene material
to significantly boost the energy density of electrochemical capacitors, putting them on a par with lead acid batteries.
but allows electrochemical capacitors to maintain their high power density (the amount of power per unit of mass or volume), according to Xiangfeng Duan,
Electrochemical capacitors, also known as ECS or supercapacitors, are an important technology for the future of energy storage and mobile power supplies,
Because the main component of an EC is its electrode material, which is responsible for the EC's overall performance,
A high-performance EC electrode must have high electrical conductivity, a high ion-accessible surface area, a high ionic transport rate and high electrochemical stability.
Current state-of-the-art ECS generally use porous activated carbon electrodes with energy densities much lower than lead acid batteries to 5 watt hours per kilogram vs. 25 to 35 watt hours per kilogram (5
In their study, published online August 8 in the journal Nature Communications, the CNSI researchers led by Duan used a highly interconnected 3d holey graphene framework as the electrode material to create an EC with unprecedented performance.
The electrode demonstrates superior electrical conductivity, exceptional mechanical flexibility and unique hierarchical porosity, ensuring the efficient transport of electrons
Furthermore, the team has shown that a fully packaged EC exhibits unparalleled energy densities of 35 watt hours per kilogram (49 watt hours per liter) bout five to 10 times higher than current commercial supercapacitors and on a par
"The holey grahene EC bridges the energy density gap between traditional capacitors and batteries, yet with vastly higher power density,"Duan said."
#On the frontiers of cyborg science No longer just fantastical fodder for sci-fi buffs, cyborg technology is bringing us tangible progress toward real-life electronic skin, prosthetics and ultraflexible circuits.
pioneering scientists are working on the seamless marriage between electronics and brain signaling with the potential to transform our understanding of how the brain worksnd how to treat its most devastating diseases.
ultraflexible electronics into the brain and allow them to become fully integrated with the existing biological web of neurons.
It is hoped the material can be used to coat the electrodes of supercapacitorslectrochemical components that can store extremely large amounts of electrical energyhilst also offering a solution to the growing environmental problem caused by used-cigarette filters.
Carbon is the most popular material that supercapacitors are composed of due to its low cost high surface area high electrical conductivity and long term stability.
A high-performing supercapacitor material should have a large surface area which can be achieved by incorporating a large number of small pores into the material continued Professor Yi.
which is an essential property in a supercapacitor for the fast charging and discharging. Once fabricated the carbon-based material was attached to an electrode
and tested in a three-electrode system to see how well the material could adsorb electrolyte ions (charge) and then release electrolyte ions (discharge).
The material stored a higher amount of electrical energy than commercially available carbon and also had a higher amount of storage compared to graphene
Nano-supercapacitors for electric cars More information: Preparation of energy storage material derived from a used cigarette filter for a supercapacitor electrode Nanotechnology iopscience. iop. org/0957-4484/25/34/345601 5
#Nanoscale biodegradable drug-delivery method could provide a year or more of steady doses About one in four older adults suffers from chronic pain.
At the Vienna University of Technology, Thomas Mueller, Marco Furchi and Andreas Pospischil have managed to create a semiconductor structure consisting of two ultra-thin layers,
Now, this semiconductor has successfully been combined with another layer made of molybdenum disulphide, creating a designer-material that may be used in future low-cost solar cells.
His team was the first to combine two different ultra-thin semiconductor layers and study their optoelectronic properties.
Tungsten diselenide is a semiconductor which consists of three atomic layers. One layer of tungsten is sandwiched between two layers of selenium atoms."
"We had already been able to show that tungsten diselenide can be used to turn light into electric energy
But a solar cell made only of tungsten diselenide would require countless tiny metal electrodes tightly spaced only a few micrometers apart.
metallic electrodes can be used, through which the charge is sucked away -or a second material is added."
#Surprise discovery could see graphene used to improve health (Phys. org) chance discovery about the'wonder material'graphene already exciting scientists because of its potential uses in electronics,
or positive electrode, of electrical vehicle batteries-as the battery charged.""We wanted to catch
Many previous methods used to analyze such battery materials have produced data that average out effects over the entire electrode.
they also conducted the same in operando study using smaller amounts of electrode material than would be found in a typical battery.
while the electrode is charging, show that lithiated (red) and delithiated (green) iron phosphate phases coexist within individual particles.
That is, in some regions of the electrode all the lithium ions are removed leaving only iron phosphate behind,
and the electrode's capacity is well below the maximum level.""This is the first time anyone has been able to see that delithiation was happening differently at different spatial locations on an electrode under rapid charging conditions,
"Jun Wang said. Slower charging, in contrast, results in homogeneous delithiation, where lithium iron phosphate particles throughout the electrode gradually change over to pure iron phosphate
-and the electrode has a higher capacity. Scientists have known for a while that slow charging is better for this material,
"but people don't want to charge slowly, "said Jiajun Wang, the lead author of the paper."
For example, the phase transformation may happen more efficiently in some parts of the electrode than others due to inconsistencies in the physical structure or composition of the electrode-for example,
manufacturers might want to look at ways to prepare the electrode so that all parts of it are the same,
The study may have great implications to a multi-billion dollar electronics industry that seeks to revolutionize technology at scales 80000 times smaller than the human hair.
A metal semiconductor and insulator purified silicon is extremely stable and has become essential to the integrated circuits and transistors that run most of our computers.
Both silicene and silicon should react immediately with oxygen but they react slightly differently. In the case of silicon oxygen breaks some of the silicon bonds of the first one
For example it might eventually be embed possible to these printed flexible optoelectronic devices into clothes packaging wall papers posters touch screens or even buildings.
and characterize inkjet printed 2d crystal-based flexible photodetectors and study their integration with commercial electronics.
or printed over any irregular surface substantially increasing the quality of printed and flexible electronics.
This represents a strong limitation for flexible electronics in a wide range of applications from active matrix displays to ultrafast light detectors and gas sensors.
of science and technology with attractive physical properties for (opto) electronics sensing catalysis and energy storage. These 2d crystals can be exfoliated from layered compounds.
The graphene-based ink enables cost-effective printed electronics on plastic. Felice explains: Other conductive inks are made from precious metals such as silver
and the team at the Cambridge Graphene Centre have been looking to formulate a set of inks based on various 2d crystals setting a new platform for printed electronics.
This will create an entirely new set of tools for printable electronics with conductive semiconducting
and environmental compatibility are key benefits to improving flexible optoelectronics Explore further: Formation of organic thin-film transistors through room-temperature printin n
which can be applied as high performance electrodes for secondary batteries and fuel cells. Yung-Eun Sung is both a group leader at the Center for Nanoparticle Research at Institute for Basic Science*(IBS) and a professor at the Seoul National University.
lithium secondary batteries, sensors, and semiconductors
#A crystal wedding in the nanocosmos Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Vienna University of Technology and the Maria Curie-Sklodowska University Lublin have succeeded in embedding nearly perfect semiconductor crystals
into a silicon nanowire. With this new method of producing hybrid nanowires, very fast and multifunctional processing units can be accommodated on a single chip in the future.
Nano-optoelectronics are considered the cornerstone of future chip technology, but the research faces major challenges:
on the one hand, electronic components must be accommodated into smaller and smaller spaces. On the other hand, what are known as compound semiconductors are to be embedded into conventional materials.
In contrast to silicon, many of such semiconductors with extremely high electron mobility could improve performance of the most modern silicon-based CMOS technology.
Scientists from the HZDR, Vienna University of Technology and Maria Curie-Sklodowska University Lublin have now come a step closer to both these targets:
they integrated compound semiconductor crystals made of indium arsenide (Inas) into silicon nanowires, which are suited ideally for constructing increasingly compact chips.
This integration of crystals was the greatest obstacle for such"hetero-nanowires"until now: beyond the nanometer range, crystal lattice mismatch always led to numerous defects.
"while the implanted atoms form the indium arsenide crystals.""Dr. Wolfgang Skorupa, the head of the research group adds:"
"In the next step, the scientists want to implement different compound semiconductors into Silicon nanowires and also optimize the size and distribution of the crystals a
#Tiny laser sensor heightens bomb detection sensitivity New technology under development at the University of California,
UC Berkeley professor of mechanical engineering, has found a way to dramatically increase the sensitivity of a light-based plasmon sensor to detect incredibly minute concentrations of explosives.
They put the sensor to the test with various explosives 2 4-dinitrotoluene (DNT), ammonium nitrate and nitrobenzene and found that the device successfully detected the airborne chemicals at concentrations of 0. 67 parts per billion, 0. 4 parts per billion and 7. 2 parts
The researchers noted that this is much more sensitive than the published results to date for other optical sensors."
"Optical explosive sensors are very sensitive and compact, "said Zhang, who is also director of the Materials science Division at the Lawrence Berkeley National Laboratory and director of the National Science Foundation Nanoscale Science and Engineering Center at UC Berkeley."
"The ability to magnify such a small trace of an explosive to create a detectable signal is a major development in plasmon sensor technology,
"The new sensor could have many advantages over current bomb-screening methods.""Bomb-sniffing dogs are expensive to train
Our technology could lead to a bomb-detecting chip for a handheld device that can detect the tiny-trace vapor in the air of the explosive's small molecules."
"The sensor could also be developed into an alarm for unexploded land mines that are otherwise difficult to detect,
Unstable and hungry for electrons The nanoscale plasmon sensor used in the lab experiments is much smaller than other explosive detectors on the market.
It consists of a layer of cadmium sulfide, a semiconductor, laid on top of a sheet of silver with a layer of magnesium fluoride in the middle.
In designing the device the researchers took advantage of the chemical makeup of many explosives, particularly nitro-compounds such as DNT and its more well-known relative, TNT.
This quality increases the interaction of the molecules with natural surface defects on the semiconductor.
Potential use to sense hard-to-detect explosive"We think that higher electron deficiency of explosives leads to a stronger interaction with the semiconductor sensor"
Because of this, the researchers are hopeful that their plasmon laser sensor could detect pentaerythritol tetranitrate, or PETN, an explosive compound considered a favorite of terrorists.
Latest generation of plasmon sensors The sensor represents the latest milestone in surface plasmon sensor technology,
The ability to increase the sensitivity of optical sensors had traditionally been restricted by the diffraction limit,
The new device builds upon earlier work in plasmon lasers by Zhang's lab that compensated for this light leakage by using reflectors to bounce the surface plasmons back and forth inside the sensor similar to the way sound waves are reflected across the room
and using the optical gain from the semiconductor to amplify the light energy. Zhang said the amplified sensor creates a much stronger signal than the passive plasmon sensors currently available
which work by detecting shifts in the wavelength of light.""The difference in intensity is similar to going from a light bulb for a table lamp to a laser pointer,
Fortunately researchers have pinpointed now the breaking mechanism of several monolayer materials hundreds of times stronger than steel with exotic properties that could revolutionize everything from armor to electronics.
and whether they acted as metals semiconductors or insulators under strain. Toggling between or sustaining those conductive properties are particularly important for future applications in microelectronics.
Testing all the different atomic configurations for each material under strain boils down to a tremendous amount of computation Isaacs said.
#Nanophotonics experts create powerful molecular sensor Nanophotonics experts at Rice university have created a unique sensor that amplifies the optical signature of molecules by about 100 billion times.
Researchers at Rice's Laboratory for Nanophotonics (LANP) said the single-molecule sensor is about 10 times more powerful that previously reported devices."
"Ours and other research groups have been designing single-molecule sensors for several years, but this new approach offers advantages over any previously reported method,
"The ideal single-molecule sensor would be able to identify an unknown moleculeven a very small oneithout any prior information about that molecule's structure or composition.
"The optical sensor uses Raman spectroscopy, a technique pioneered in the 1930s that blossomed after the advent of lasers in the 1960s.
By using CARS in conjunction with a light amplifier made of four tiny gold nanodiscs,
Zhang said the quadrumer amplifiers are a key to SECARS, in part because they are created with standard e-beam lithographic techniques,
The manufacture of`super-black`carbon nanotube-based materials has required traditionally high temperatures preventing their direct application to sensitive electronics or materials with relatively low melting points.
which period Surrey Nanosystems successfully transferred its low-temperature manufacturing process from silicon to aluminum structures and pyroelectric sensors.
and long-term vibration and is suitable for coating internal components such as apertures baffles cold shields and Micro Electro Mechanical systems (MEMS)- type optical sensors.
and hence, optical properties of select antennas. Therefore, one can decide after fabrication, rather than before,
The team demonstrated that an electron beam from a standard scanning electron microscope (SEM) can be used to deform either individual p-BNA structures
His research is centered on building better lithium ion batteries, primarily for personal electronics and electric vehicles. He is focused on the anode
but as electronics have become more powerful graphite's ability to be improved has been tapped virtually out.
Building smaller greener electronics In the drive to get small, Robert Wolkow and his lab at the University of Alberta are taking giant steps forward.
when using traditional transistor-based integrated circuits. That's why he and his research team are aiming to build entirely new technologies at the atomic scale."
"Our ultimate goal is to make ultra-low-power electronics because that's what is demanded most by the world right now,
"It could be as important as the transistor, "says Wolkow.""It lays the groundwork for a whole new basis of electronics,
and in particular, ultra-low-power electronics.""Wolkow and his team have built upon their earlier successes, modifying scanning tunnelling microscopes with their atom-wide microscope tip,
which emits ions instead of light at superior resolution. Like the needle of a record player, the microscopes can trace out the topography of silicon atoms, sensing surface features on the atomic scale.
"Much of their efforts initially will focus on creating hybrid technologiesdding atom-scale circuitry to conventional electronics such as GPS devices
#Designing ultra-sensitive biosensors for early personalised diagnostics A new type of high-sensitivity and low-cost sensors,
amplifying the light radiation in hot spots regions of the antenna, explains Pietro Giuseppe Gucciardi, a physicist at the Institute for Chemical-Physical Processes, affiliated with the Italian National Research Council CNR, in Messina,
She adds that these biosensors will need to be integrated with optical components, with electronics for reading out the measurements, software to process all data,
The team analyzed the solar cell activity of their nanohole interfaces by coating them with a semiconducting polymer and metal electrodes.
The newly developed material can be used as a substitute for graphene in solar cells and semiconductor chips.
and directly used the transparent electrodes for organic solar cells. The research outcome was introduced in Nanoscale a journal of Royal Society of Chemistry in the UK under the title of One-step Synthesis of Carbon Nanosheets Converted from a Polycylic Compound
and Their Direct Use as Transparent Electrodes of ITO-free Organic solar cells and was selected as a cover story in the January 21st edition in recognition for this innovative and superb research findings.
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