Tag Archives: nanotechnology

Coulomb Transistor — A New Concept Where Metal Nanoparticles Are Used In Place Of Semiconductor

A research group at the University of Hamburg has created a unique coulomb transistor that operates on the principle of the voltage control of the electron band gap in metallic quantum-dot nanoparticles. This Single-electron transistor represents an approach to develop less power-consuming microelectronic devices. It will be possible if industry-compatible fabrication and room temperature operation are achieved.

The concept is based on building stripes of small, colloidal, metal nanoparticles on a back-gate device architecture. Being very tiny, the metallic nanoparticles exhibit semiconductor properties that can be controlled by voltage. The body of this transistor can be operated as a second gate. It results in well-defined and controllable transistor characteristics.

Design of coulomb transistor
Design of Coulomb transistor

This newly invented Coulomb transistor has three main advantages. The advantages are: on/off ratios above 90%, very reliable and sinusoidal Coulomb oscillations, and room temperature operation. The concept allows for tuning of the device properties such as Coulomb energy gap and threshold voltage, as well as the period, position, and strength of the oscillations.

Though the single-electron transistor (SET) is quite similar to a common field-effect transistor (FET), it does not rely on the semiconductor band gap but instead on the Coulomb energy gap. Transfer characteristics of the SET show periodic on and off states known as Coulomb oscillations. Researchers hope that might render new applications possible in the future.

When a bias voltage is applied to the nanoparticle channel, it becomes clear that conduction in this system is not purely metallic but is controlled by tunnel barriers between individual particles. The transport of charged particles is hindered due to very high potential barrier which depends on the charging energy. Tuning the voltage of an additional gate results in a field effect that continuously shifts the energy levels of the particles and allows for tunneling to occur. This additional gate electrode is separated from the channel by a dielectric layer.

Output characteristics of coulomb transistor
Output characteristics of Coulomb transistor

The single-electron transistors require further research and more development, but the work shows that there are alternatives to traditional transistor concepts that can be used in the future in various fields of application. Christian Klinke, the lead researcher, said in a statement,

The devices developed in our group can not only be used as transistors, but they are also very interesting as chemical sensors because the interstices between the nanoparticles, which act as so-called tunnel barriers, react highly sensitive to chemical deposits.

SUNY Polytechnic Creates 3-in-1 Device That Can Be A Diode, A MOSFET And A BJT

In a recently published study, a team of researchers at SUNY Polytechnic Institute in Albany, New York, has suggested that combining multiple functions in a single semiconductor device can significantly improve device’s functionality and efficiency.

Nowadays, the semiconductor industry is striving to scale down the device dimensions in order to fit more transistors onto a computer chip and thus improve the speed and efficiency of the devices. According to Moore’s law, the number of transistors on a computer chip cannot exponentially increase forever. For this reason, scientists are trying to find other ways to improve semiconductor technologies.

To demonstrate the new technology which can be an alternative to Moore’s law, the researchers of SUNY Polytechnic designed and fabricated a reconfigurable device that can be a p-n diode (which functions as a rectifier), a MOSFET (for switching), and a bipolar junction transistor (or BJT, for current amplification). Though these three devices can be fabricated individually in modern semiconductor fabrication plants, it often becomes very complex if they are to be combined.

reconfigurable 3-in-1 semiconductor device
the reconfigurable 3-in-1 semiconductor device

Ji Ung Lee at the SUNY Polytechnic Institute said,

We are able to demonstrate the three most important semiconductor devices (p-n diode, MOSFET, and BJT) using a single reconfigurable device. We can form a single device that can perform the functions of all three devices.

The multitasking device is made of 2-D tungsten diselenide (WSe2), a new transition metal dichalcogenide semiconductor. This class of materials is special as the bandgap is tunable by varying the thickness of the material. It is a direct bandgap while in single layer form.

Another challenge was to find a suitable doping technique as WSe2 lacks one being a new material. So, to integrate multiple functions into a single device, the researchers developed a completely new doping method. By doping, the researchers could obtain properties such as ambipolar conduction, which is the ability to conduct both electrons and holes under different conditions. Lee said,

Instead of using traditional semiconductor fabrication techniques that can only form fixed devices, we use gates to dope.

These gates can control which carriers (electrons or holes) should flow through the semiconductor. In this way, the ambipolar conduction is achieved. The ability to dynamically change the carriers allows the reconfigurable device to perform multiple functions. Another advantage of using gates in doping is, it saves overall area and enable more efficient computing. As consequence, the reconfigurable device can potentially implement certain logic functions more compactly and efficiently.

In future, researchers plan to investigate the applications of this new technology and want to enhance its efficiency further. As Lee said,

We hope to build complex computer circuits with fewer device elements than those using the current semiconductor fabrication process. This will demonstrate the scalability of our device for the post-CMOS era.

Early Diagnosis Now Possible With Smart Bandage

IoE era is here since we are able now to add mobile radio capabilities in our applications! The latest incarnation of the cell phone network will offer internet connectivity and possibilities that could only be dreamt of previously depending on your standpoint, and many more factors.

And now let’s embed these concept in medical applications, like “Smart Bandage” . It is conceivable that sensors embedded in a medical dressing could continuously monitor the wound healing process and send alerts to medical personnel when an infection is detected.  Maybe the patient could not tell accurately  since the pain is not a valid indicator of biological dysfunction. The problem is that we all have different thresholds; some stalwarts may endure the pain and only end up visiting a doctor as a last resort when the simple infection has developed into something nastier. Other patients will be convinced that a slight twinge is evidence of a life threatening condition. An objective assessment of the patient’s state of health will not only be reassuring to the patient, but also lead to a more efficient use of medical resources and reduced health care costs.

For this reason, band-aids with sensors and 5G network interfaces seem like a win-win formula. They will give the doctor an early indication of problems and may even be able to run rudimentary diagnostics to indicate the cause of the problem. Instead of long waiting times for appointments and expensive laboratory tests we could, for example get an immediate recommendation of an effective antibiotic. This is just one small example of the many benefits that the IoE will eventually bring to medical care in the future.

“That intelligent dressing uses nano-technology to sense the state of that wound at any one specific time. It would connect that wound to a 5G infrastructure and that infrastructure through your telephone will also know things about you – where you are, how active you are at any one time. You combine all of that intelligence so the clinician knows the performance of the specific wound at any specific time and can then tailor the treatment protocol to the individual and wound in question.” – Prof Marc Clement, chairman of the Institute of Life Science (ILS).

 

Via: Elektor

Reliable molecular switch

by Eric Bogers @ elektormagazine.com:

Nanotechnology repeatedly breaks new records in the area of miniaturization. However, there are physical limits when reducing the size of electronic components and these will be reached in the near future. This means that new materials and components will be required – and it is here where molecular electronics will play a role. Researchers from the Karlsruher Institut für Technologie (KIT) have succeeded in developing a molecular toggle switch, which will not only remain in the selected position, but can also be switched as often as desired without any deformation taking place.

Reliable molecular switch – [Link]

Super Efficient Nano-LED

For the exponentially growing data traffic worldwide, the data connections within and between microchips are increasingly becoming a bottleneck. Optical connections are an obvious successor, but that requires an adequate nano-sized light source – and this has now been found. Researchers from the TU Eindhoven have succeeded in making a nano-LED with an efficiency 1000 times greater than its predecessors, and which can operate at a data rate of gigabits per second.


The data connections between microchips (the so-called interconnects) are responsible for the majority of the energy consumption of these chips – one of the reasons why there is a worldwide search for optical (photonic) interconnects. The problem here is the light source: it has to be small enough to fit in the microscopic structure of the microchips. The output power and efficiency also have to be high enough – and especially the latter was a challenge.

The LED that was developed at the TU Eindhoven has a size of only a few hundred nanometers and has a integrated light channel (wave guide) for transporting the light signal. The increase in the efficiency of this new LED was mostly due to the quality of the coupling of the LED to that light channel.

The research is described in the paper ‘Waveguide-coupled nanopillar metal-cavity light-emitting diodes on silicon’ that appeared in Nature Communications; it can be viewed here.
Source: Elektor

Human Motion Powered Nanotechnology Devices

Michigan State University researchers have came up with a new method for  harvesting energy from human motion using nanotechnology. They designed a low-cost film-like device, a nanogenerator, than can power a LCD display,  keyboard, and some LEDs without any source of electric power, by only using some human touching or pressing.

This device called FENG, biocompatible ferroelectret nanogenerator, consists of several thin layers of silicon wafer made of environmentally friendly substances like silver, polyimide, and polypropylene ferroelectret – which is introduced here as the active material of this device. To add the electrical powering feature, researchers added ions to each layer to make sure that each layer has its own charged particles. Finally the circuit works only once some pressure or mechanical energy is performed on the device. For example, by using this technology you will be able to power the LED lights with the pressure of your palm, while the pressure of your finger is enough to power the LCD screen.

In this video 20 LEDs are powered with hand pressing:

Researchers’ investigations had shown that the voltage and current generated by pressure can be doubled if the device is folded, means a high-frequency pressure is already demonstrated.

“Each time you fold it you are increasing exponentially the amount of voltage you are creating,” said Nelson Sepulveda, associate professor of electrical and computer engineering and lead investigator of the project. “You can start with a large device, but when you fold it once, and again, and again, it’s now much smaller and has more energy. Now it may be small enough to put in a specially made heel of your shoe so it creates power each time your heel strikes the ground.”

Sepulveda believes that implementing this technology in real life will shift wearables to be completely powered by human motion. He and his team are working now on transmitting the power generated from the heel strike to be used for powering other devices like a headset.

In this video you can take a look at the flexible keyboard they designed:

This research was funded by the National Science Foundation. You can learn more about this project by checking the scientific paper, and the university official website.

These tiny batteries can be charged in seconds and last for a week

Battery anxiety is a modern day problem for many of us. Mobile phone and wearable technologies are getting developed rapidly, but battery issues seem to be neverending. As phones and wearables are getting thinner, there needs to be a trade-off between battery life and design. Scientists are searching for a way to make a battery that’s tiny yet capable of holding the charge for a long time. So, what’s the solution? Supercapacitor.

Flexible Laser Scribed Graphene Supercapacitor
Flexible Laser Scribed Graphene (LSG) Supercapacitor

Scientists have been researching on the use of nanomaterials to improve supercapacitors that could enhance or even replace batteries in electronic devices. But it’s not an easy task. Considering a typical supercapacitor, it must be a large one to store as much energy as a Li-ion battery holds.

To tackle the battery issue, a team of scientists at the University of Central Florida (UCF) has created a tiny supercapacitor battery applying newly discovered two-dimensional materials with only a few atoms thick layer. Surprisingly, the new process created at UCF yields a supercapacitor that doesn’t degrade even after it’s been recharged/discharged 30,000 times. Where a lithium-ion battery can be recharged less than 1,500 times without significant failure.

So, what else makes the supercapacitor special apart from their tiny size? Well, let’s hear it from Nitin Choudhary, a postdoctoral associate who conducted much of the research :

If they were to replace the batteries with these supercapacitors, you could charge your mobile phone in a few seconds and you wouldn’t need to charge it again for over a week.

Supercapacitors are not used in mobile devices for their large size. But the team at UCF has developed supercapacitors composed of millions of nanometer-thick wires coated with shells of two-dimensional materials. A highly conductive core helps fast electron transfer for fast charging and discharging. And uniformly coated shells of two-dimensional (2D) materials produce high energy and power densities.

Nanowire Supercapacitor Made of Capacitive 2D WS2 Layers
Nanowire Supercapacitor Made of Capacitive 2D WS2 Layers

Scientists already knew 2D materials held great promise for energy storage purpose. But until the UCF developed the process for integrating those materials, it was not possible to realize that potential. Nitin Choudhary said,

For small electronic devices, our materials are surpassing the conventional ones worldwide in terms of energy density, power density, and cyclic stability.

Supercapacitors that use the new materials could be used in phones, wearables, other electronic gadgets, and electric vehicles. Though it’s not ready for commercialization yet. But the research team at UCF hopes this technology will soon end the battery problem of smartphones and other devices. So let’s wait awhile, and at the end of this year maybe you’ll be using a new smartphone that can be charged in seconds and lasts for a week, who knows!

Nanotechnoloy – Nano coating prevents exploding Li-ion batteries

Lithium-ion batteries are very popular as they’re lightweight and have high energy density. But at the same time, li-ion batteries are very sensitive to overcharge/over discharge. An internal short circuit can cause fire and it may even lead to a violent explosion. Fortunately, nanotechnology found a way to prevent this kind of nightmare. How? let’s discuss:

Why Does li-ion Battery Explode?

When a device draws too much power from a Li-Ion battery, it heats up and thus melts the internal separator between the two flammable electrolytes. This phenomenon ignites a chemical reaction between the electrolytes causing them to explode. Once their package ruptures, the oxygen in the surrounding air helps the flammable electrolytes to catch fire. The fire then spreads quickly to other cells and loads a thermal runaway.

Thermal runaway in Li-ion Battery
Thermal runaway in Li-ion Battery

During a thermal runaway, the high heat of the damaged or malfunctioning cell can propagate to the next cell, causing it to become completely thermally unstable as well. In some worse cases, a chain reaction occurs in which each cell disintegrates at its own timetable.

So, in a nutshell, Li-ion cells possess the potential of a thermal runaway. The temperature quickly rises to the melting point of the metallic lithium and cause a violent reaction, which finally causes an explosion.

How Can Nanotechnology Prevent This?

Recently conducted research shows that atomic layer deposition (ALD) of titania (TiO2) and alumina (Al2O3) on Ni-rich FCG NMC and NCA active material particles could substantially improve Li-ion battery’s performance and allow for increased upper cutoff voltage (UCV) during charging, which delivers significantly increased specific energy utilization.

Atomic Layer Deposition in li-ion CellsAtomic Layer Deposition in li-ion Cells
Atomic Layer Deposition in li-ion Cells

 

A company called Forge Nano claims to prevent this thermal runaway situation by never letting it get started even if the battery electrodes are shorted out. Forge Nano’s precision coatings on cathode and anode powders protect against the most common degradation mechanisms found in Li-ion batteries.

The benefits of Forge Nano precision coatings include extended battery life and greater safety, especially in extreme situations such as high-temperature operation, fast cycling rates, and overvoltage conditions.

By implementing lithium-based ALD films in nanostructured 3D lithium-ion batteries, significant gains in power density, cycling performances during charge/discharge, and safety is noticed.

What’s the Result?

Some of Forge Nano’s accomplishments in the Li-ion battery space includes:

  • Increased lifetime of commercial cathode material by as much as 250%
  • 15% higher energy density in large format pouch cells (40 Ah) that pass nail penetration testing
  • 60% reduced gas generation in cathode material
  • A low-cost high-voltage cathode powder with exceptional performance
  • Increased rate capability of conventional materials for enhanced fast charge acceptance using Forge Nano’s proprietary solid electrolyte coatings

    ForgeNano Claims Their Technology as Best Solution
    ForgeNano Claims Their Technology as Best Solution

Since the solution found by the research, Forge Nano has been working on a commercial version of the product that they finally believe they can place in the market very soon.

Nanobots Fight Cancerous Cells

Researchers from Polytechnique Montréal, Université de Montréal and McGill University have just achieved a spectacular breakthrough in cancer research. They have developed new nanorobotic agents capable of navigating through the bloodstream to administer a drug with precision.

Professor Sylvain Martel is holder of the Canada Research Chair in Medical Nanorobotics and the Director of the nanorobotics laboratory at Polytechnique Montreal, where he studies medical applications of nanotechnology. Martel and his team have demonstrated major progress with a new technology that could revolutionize cancer treatment by using guided micro-transporters to deliver drugs. Thus cancerous cells can be locally targeted and then stop their growth.

new_version-b-low

This breakthrough in cancer-fighting research would ditch chemotherapy for nanorobots that fight cancer inside the human body. This research was published in the prestigious journal Nature Nanotechnology in an article titled “Magneto-aerotactic bacteria deliver drug-containing nanoliposomes to tumour hypoxic regions.” The article notes the results of the research done on mice, which were successfully administered nanorobotic agents into colorectal tumours.

“These legions of nanorobotic agents were actually composed of more than 100 million flagellated bacteria — and therefore self-propelled — and loaded with drugs that moved by taking the most direct path between the drug’s injection point and the area of the body to cure,” explains Professor Martel “The drug’s propelling force was enough to travel efficiently and enter deep inside the tumours.”

When they enter a tumour, the nanorobotic agents can detect in a wholly autonomous fashion the oxygen-depleted tumour areas, known as hypoxic zones, and deliver the drug to them. This hypoxic zone is created by the substantial consumption of oxygen by rapidly proliferative tumour cells. Hypoxic zones are known to be resistant to most therapies, including radiotherapy. But gaining access to tumours by taking paths as minute as a red blood cell and crossing complex physiological micro-environments does not come without challenges. So Professor Martel and his team used nanotechnology to do it.

Scanning electron microscopy images of unloaded Magneto-aerotactic(MC-1) bacteria (Left) and when loading it with the drug (right)
Scanning electron microscopy images of unloaded Magneto-aerotactic(MC-1) bacteria (Left) and when loading it with the drug (right)

To move around, bacteria used by Professor Martel’s team rely on two natural systems; a kind of compass created by the synthesis of a chain of magnetic nanoparticles allows them to move in the direction of a magnetic field, while a sensor measuring oxygen concentration enables them to reach and remain in the tumour active regions. By harnessing these two transportation systems and by exposing the bacteria to a computer-controlled magnetic field, researchers showed that these bacteria could perfectly replicate artificial nanorobots of the future designed for this kind of task.

“These results represent a novel therapeutic avenue for patients with hard-to-treat cancers, once the approach has been validated in human trials,” says co-author Nicole Beauchemin, a professor of Biochemistry, Medicine and Oncology at McGill and researcher at the Rosalind and Morris Goodman Cancer Research Centre.

An interview with Professor Martel with RT America to explain how the nanorobots are better at targeting cancer cells than current cancer treatments.

This work was supported by many research centers and consortiums in Canada such as the Consortium québécois sur la découverte du médicament (Québec consortium for drug discovery – CQDM), the Canada Research Chairs, the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Research Chair in Nanorobotics of Polytechnique Montréal.

To overcome some limitations of the previous approach, professor Martel has been leading a new research that uses the Particle Swarm Optimization (PSO) algorithm to increase the number of dimensions in the search space and to optimize targeting cancer cells in blood. This research took part at 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems recently on October.

Besides replacing the toxic chemotherapy that has plenty of harmful side effects on the entire human body, this research will not only open doors for new inventions and applications, but it also will pave the way for inventing new medical, imaging and diagnostic agents.

You can find more details, videos and photos in this media kit from Université de Montréal. You can also check this TEDx talk by Professor Martel about using nanotechnology in healing cancer.

A New Record for Single-molecule Diode

Diodes are one of the most common used electronic components in our designs used to direct the current flow. Single-molecule electronics is a “branch of nanotechnology that uses single molecules, or nanoscale collections of single molecules, as electronic components.” according to Wikipedia definition, and shrinking the size of components is one of the biggest target researchers are looking forward.

20160418113808_Diode-molecuul

The concept of Single-molecule diode was introduced in 1974 by Aviram & Ratner, and the single-molecule diode consists of an asymmetric molecule which includes a donor–bridge–acceptor architecture to mimic a semiconductor p–n junction.

The performance of single-molecule diode still need improvement, compared to the performance of the conventional ones, and that’s what researchers are trying to do. Recently, Researchers at TU Delft in the Netherlands made a single molecule diode with a rectification ratio of 600 much higher than the value of 15 measured in earlier research.

Via: elektormagazine