Application of Nanotechnology in Smart Electronics
Electronic gadgets and their components are becoming increasingly tiny. Consumer need for smaller gadgets with the same performance and effectiveness, if not better, than previous ‘bulkier’ technologies has propelled this trend. Traditional materials can only go so far until they can no longer be made any smaller. Nanoelectronics provides some answers to how we might improve the capabilities of electronics while reducing their weight and energy consumption.
After more than two decades of basic nanoscience research and more than fifteen years of dedicated R&D under the NNI, nanotechnology applications are delivering on nanotechnology’s promise to improve society in both expected and unforeseen ways. Many technological and industrial areas, including information technology, homeland security, health, transit, energy, food security, and environmental research, are being significantly improved, if not revolutionized, by nanotechnology. Many of the advantages of nanotechnology are based on the ability to change the frameworks of materials at extremely tiny sizes to obtain specific features, considerably expanding the materials science toolset. Materials can be made stronger, lighter, more durable, reactive, sieve-like, or better electrical conductors using nanotechnology, among other properties. Many commercial items that rely on nanoscale materials and techniques are now on the market and in use.
Nanotechnology is a branch of research and invention. It focuses on creating things on the scale of atoms and molecules. A nanometre is one-billionth of a meter in length or ten times the diameter of a hydrogen atom. The term nanoelectronics refers to the use of nanotechnology in electronic components. These components are often only a few nanometers in size. However, the tinier electronic components become, the harder they are to manufacture. Nanoelectronics covers a diverse set of devices and materials, with the common characteristic that they are so small that physical effects alter the properties of the material on a nanoscale — inter-atomic interactions and quantum mechanical properties play a significant role in the workings of these devices. At the nanoscale, new phenomena take precedence over those that hold sway in the macro-world. Quantum effects such as tunneling and atomistic disorder dominate the characteristics of these nanoscale devices.
Nanotechnology in electronics offers faster, smaller, and more portable systems. Nanoelectronics increases the capabilities of electronic devices, enhances the density of memory chips, reduces power consumption and the size of transistors used in integrated circuits, and enhances the density of memory chips to manage and store larger amounts of data and information. It provides magnetic nanoparticles for data storage, printable and flexible electronics, and advanced display technologies with quantum computing and conductive nanomaterials. Nanoelectronics can improve display screens on electronic devices and revolutionize a lot of electronic products, applications, and procedures and reduce their weight, power consumption, and the size of transistors used in integrated circuits. Nanoelectronics is sometimes a controversial technology because the current candidates are statistically significantly different from conventional transistors. Some nanoelectronic candidates include carbon nanotubes, silicon nanowires, hybrid molecular/semiconductor electronics, or advanced molecular electronics.
So let’s get a deeper insight into nanoscale materials and how are they revolutionizing mankind!
NANOMATERIALS IN ELECTRONICS
- Fullerenes
Fullerenes are a family of substances made of carbon in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are commonly known simply as fullerenes (C60) or now less frequently as ‘Bucky balls’ and have been researched for use in electronics and other applications. Tubular fullerenes, generally called carbon nanotubes, are considered possibly the most famous objects in nanotechnology and possess extraordinary properties arising from their nanoscopic dimensions. They were discovered in 1991 in the insoluble material of arc-burned graphite rods.
2. Carbon Nanotubes
Carbon nanotubes are molecules that are composed only of carbon atoms and are markedly different from bulk graphite. They can be viewed as a graphene sheet rolled into a cylinder and seamlessly welded together. Carbon nanotubes exist in either of two forms, single-wall carbon nanotubes, and multi-wall carbon nanotubes. Single-wall nanotubes consist of a single graphene layer while multi-wall nanotubes consist of multiple concentric layers. In addition to the synthetic production of carbon nanotubes for research and commercial purposes, it has recently been discovered that multi-wall carbon nanotubes were present in particulate matter collected from propane or natural gas kitchen stoves. Multi-wall carbon nanotubes were also found in particulate matter collected in outdoor air, with one possible source being car exhaust fumes.
Carbon nanotubes can be either ‘metallic’ or semiconducting depending on the actual way in which the carbon atoms are assembled in the tube. The metallic forms possess electrical conductivities 1000 times greater than copper and are now being mixed with polymers to make conducting composite materials for applications such as electromagnetic shielding in mobile phones and static electricity reduction in cars. Their use has been demonstrated in supercapacitors for energy storage, field emission devices for flat panel displays, and nanometer-sized transistors
3. Quantum Dots
Quantum dots are semiconductor nanocrystals (2–100 nm) that have unique optical and electrical properties. In structure, quantum dots consist of a metalloid crystalline core and a ‘cap’ or ‘shell’ that shields the core. Quantum dot cores can be formed from a variety of metal conductors such as semiconductors, noble metals, and magnetic transition metals. The shells are also formed of a variety of materials. Therefore, not all quantum dots are alike and they cannot be considered to be a uniform group of substances. With regard to the cores of quantum dots, group III-V series quantum dots are composed of mixtures of compounds such as indium phosphate (InP), indium arsenate (InAs), gallium arsenate (GaAs), and gallium nitride (GaN). Group II-IV series of quantum dots are composed of mixtures of compounds such as zinc sulfide (ZnS), zinc-selenium (Zn-Se), cadmium-selenium (CdSe), and cadmium-tellurium cores (CdTe).
APPLICATION OF NANOTECHNOLOGY IN COMING-OF-AGE ELECTRONICS
1. NANOSCALE TRANSISTORS
A nano transistor is a transistor, the component that acts as an electronic signal with an amplifier that is near the scale of a billionth of a meter in size (nanoscale). These nano-transistors are expected to have a gate or control electrode as short as 70nm and gate oxide, which separates the control electrode from the current-carrying channels thin as about 1nm. The semiconductor industry can manufacture logic that incorporates more than a 40million MOSFET (Metal oxide semiconductor field-effect transistors) into a single circuit and in coming years at the same cost, the semiconductor industry will manufacture logic chips that will nearly a half-billion nanometer-scale MOSFETs(nano transistors) packing about 5–10 nano transistors/µm2.
The smaller transistors, the more atomic-scale variations in their size and structure affect their performance and thus the reliability of a whole circuit. The focus is to develop new design tools and methodology for transistors and circuits at the nanoscale which will enable the manufacturing of reliable, low-cost, low electromagnetic interference, high yield complex silicon chips, and corresponding products using unreliable and variable devices. The lead semiconductor manufacturer is producing microchips with transistors less than 30 nanometers in size by comparison a human hair is around 105 nanometers wide.
2. SMART DISPLAYS
Smart Panels Nanotechnology finds application in many contemporary TVs. They are also applied to laptop computers, digital cameras, cell phones, etc. It combines nanostructured polymer films known as organic light-emitting diodes. These are also known as OLEDs. OLED screens give brighter consumption and longer lifetimes. Display technologies can be grouped into three broad technology areas; Organic LEDs, electronic paper and other devices intended to show still images, and Field Emission Displays.
OLEDs and OLETs
OLEDs organic light-emitting diodes are full of promise for a range of practical applications. OLED technology is based on the phenomenon that certain organic materials emit light when fed by an electric current and it is already used in small electronic device displays in mobile phones, MP3 players, digital cameras, and also some TV screens. With more efficient and cheaper OLED technologies it will possible to make ultra-flat, very bright, and power-saving OLED televisions, windows that could be used as light sources at night, and large-scale organic solar cells. In contrast to regular LEDs, the emissive electroluminescent layer of an OLED consists of a thin film of organic compounds.
What makes OLEDs so attractive is that they do not require a backlight to function and therefore require less power to operate; also, since they are thinner than comparable LEDs, they can be printed onto almost any substrate. Recently, researchers have even developed a brand new concept of OLEDs with a few nanometers of graphene as transparent conductors. This paved the way for inexpensive mass production of OLEDs on a large-area low-cost flexible plastic substrate, which could be rolled up like wallpaper and virtually applied to anywhere you want.
Quantum Dot LEDs (QLEDs)
Quantum dots (QDs), because they are both photo-active (photoluminescent) and electro-active (electroluminescent) and have unique physical properties, are one of the most promising optoelectronic materials and will be at the core of next-generation displays. Compared to organic luminescent materials used in organic light-emitting diodes (OLEDs), QD-based materials have purer colors, longer lifetime, lower manufacturing cost, and lower power consumption. Another key advantage of quantum dot displays is that, because QDs can be deposited on virtually any substrate, you can expect printable and flexible even rollable displays of all sizes.
Electronic paper
Unlike a conventional flat panel display, which uses a power-consuming backlight to illuminate its pixels, the electronic paper reflects light like ordinary paper and is capable of holding text and images indefinitely without drawing electricity, while allowing the image to be changed later. Because they can be produced on thin, flexible substrates and due to their paper-like appearance, electrophoretic displays are considered prime examples of the electronic paper category. Electrophoretic displays already are in commercial use, for instance in the Kindle or in the Sony Reader, but so far the displays are mostly black and white. There are still cost and quality issues with color displays. Nanotechnology researchers have shown that organic ink nanoparticles could provide an improved electronic ink fabrication technology resulting in an e-paper with high brightness, good contrast ratio, and lower manufacturing cost.
Field Emission Displays
Researchers have turned to carbon nanotubes to create a new class of large area, high resolution, low-cost flat panel displays. Some believe field emission display (FED) technology, utilizing carbon nanotubes (CNT) as electron emitters, will be the biggest threat to LCD’s dominance in the panel display arena and that FED is the technology of choice for ultra-high-definition, wide-screen televisions. FEDs, in a sense, are a hybrid of CRT televisions and LCD televisions. They capitalize on the well-established cathode-anode-phosphor technology built into full-sized CRTs using this in combination with the dot matrix cellular construction of LCDs. The electron emitters, arranged in a grid, are individually controlled by “cold” cathodes (unlike in normal CRTs, field emission does not rely on heating the cathode to boil off electrons) to generate colored light. Field emission display technology makes possible the thin panel of today’s liquid crystal displays (LCD), offers a wider field-of-view, provides the high image quality of today’s cathode ray tube (CRT) displays, and requires less power than today’s CRT displays
3. MAGNETIC RAMs
MRAM (Magnetic RAM) is a memory technology that uses electron spin to store information (an MRAM device is a Spintronics device). MRAM has the potential to become a universal memory — able to combine the densities of storage memory with the speed of SRAM, all the while being non-volatile and power efficient. MRAM technology is still far from realizing its potential, but as of early 2020, there are MRAM chips on the market ranging from very small ones to 1Gb chips, and companies are adopting this technology for many applications. Dozens of companies and research groups are developing next-generation MRAM technologies as analysts expect MRAM shipments and revenues to grow quickly in the next few years.
MRAM can resist high radiation, can operate in extreme temperature conditions, and can be tamper-resistant. Also, it can keep even encrypted data following a system shutdown or crash. This enables resume play functionality. This makes MRAM suitable for automotive, industrial, military, and space applications, and these are important segments for MRAM developers. The first MRAM devices to be realized used toggle memory switching, in which a magnetic field is used to change the electron spin.
4. NANOMATERIALS IN BATTERIES
The properties of carbon nanotubes make them potentially useful as an anode material or as an additive in lithium-ion (Li-ion) battery systems. In 2005, one article noted that the anode of Li-ion batteries is primarily made from various carbonaceous materials but that carbon nanotubes promise to boost this rate of growth, either by themselves or when incorporated into the appropriate composite material. The predominant part of commercially-produced carbon nanotubes is used for the manufacturing of porous conductive electrodes for Li-ion batteries. In 2005, Toshiba launched a rechargeable Li-ion battery that used ‘nano-particles’, although it is not clear whether carbon nanotubes or another nano-material is used. Altair Nanotechnologies Inc. developed a nano-titanate material that it uses commercially in Li-ion batteries. A123 has developed and commercialized Li-ion batteries based on nano phosphate technology (A123 2006). Other nanomaterials under investigation for use in Li-ion batteries are nanoparticles of vanadium, manganese, and cobalt compounds.
A paper battery is an interesting application of nanotechnology in batteries. A paper battery is flexible, ultra-thin energy storage and production device formed by combining two things carbon nanotube and nanocomposite paper. Nanocomposite paper is a hybrid energy storage device made of cellulose, which combines the features of supercapacitors and batteries. It takes the high energy storage capacity of the battery and high energy density of the supercapacitor producing the bursts of extreme power. The devices are formed by combining cellulose with an infusion of aligned carbon nanotubes that are each approximately one-millionth of a centimeter thick. This combination permits the battery to provide both long-term, bursts of energy, steady power, and production. Paper batteries have the potential to power the next generation of medical devices, electronics, and hybrid vehicles. They can be folded, twisted, folded, crumpled, shaped, and cut for various applications without any loss of efficiency. Paper batteries can function between -75 and 150 degrees Celsius.
5. NANOMATERIALS IN TOUCHSCREENS
Touch screens have become ubiquitous over the last decade in the form of smartphones, watches, tablets, and other applications. Despite this remarkable growth, a critical part of their underlying technology remarkably has not advanced as rapidly. Today’s electronic displays are still relatively fragile and expensive. Nano-C is revolutionizing this market with its super-strong, flexible, and low-cost carbon nanotube-based materials. Carbon nanotubes can replace or work alongside existing display materials such as Indium Tin Oxide (ITO), and new materials such as silver, enabling displays that are 250 times stronger and up to 50 percent less expensive than current technologies. This will not only extend the life of today’s products, but also drive the development of displays for many other applications that require low cost, extreme robustness, or flexibility.
Graphene Touchscreens
In 2010, an international team of physicists, including co-inventor of graphene Dr. Kostya Novoselov, published a paper in which they have described the use of the graphene in rollable e-paper, among other applications. Also, it was predicted that the super-conductive material, which is made of a single sheet of carbon atoms, will be used in the development of many future electronic devices. The researchers anticipated that graphene will replace indium tin oxide in touch screen devices in three to five years, with rollable e-paper emerging by the year 2015. A Rice University team has already conducted trials of graphene touch screens by growing a fine graphene sheet on a metal nanowire grid. Companies such as Bluestone Global Tech are already marketing sheets of graphene large enough to use in the manufacturing of electronic devices, and many electronics manufacturers are investigating using this material in their future products.
Silver Nanowires
Recently, works are going on a novel transparent conductive material using silver nanowires that can be deposited very easily, even on flexible substrates, and can reach high conductivities. The nanowires are arranged randomly across each other, creating a wired network that forms a conductive surface on the substrate. Due to the thinness of the nanowires, the network has a lot of empty spaces, making the surface transparent. The process is solution-based hence the substrates can be coated rapidly using standard roll-to-roll printing techniques, and the use of silver makes the conductivity of the material very high. These devices are designed to take advantage of the touch capability in Windows 8. The flexibility and performance of silver nanowires will enable leaps forward in industrial design, with touch-capable surfaces applied to any number of devices, even ordinary objects or structural features.
Copper Nanowires
Duke University researchers have developed a technique for producing copper nanowires at a scale that could make them a replacement for ITO in solar panels and touch screens. The water-based production process, however, caused clumping of the nanowires, decreasing their conductivity. The researchers have conducted further studies and have solved the clumping problem and according to them, copper nanowires will appear in cheaper solar cells, touch screens, and flexible electronics in the coming years. Copper nanowires can be coated in a roll-to-roll process, unlike ITO films that use a costly and slow process. Also, copper nanowires are flexible and can be used to build flexible electronics. After just a few bends, ITO films break, but copper nanowires retain their conductivity and form even if bent 1000 times. Copper nanowires are more economical than ITO and silver. Researchers believe that with constant development, they can be used in solar cells and screens leading to more reliable and lighter displays and making solar energy more competitive when compared with fossil fuels.
OTHER USE CASES OF NANOTECHNOLOGY IN ELECTRONICS
· Flash memory chips for smartphones and thumb drives
· Ultra-responsive hearing aids
· Conductive inks for printed electronics for RFID/smart cards/smart packaging
· Antimicrobial/antibacterial coatings on keyboards and cell phone casings
· Nanorobots
· Nanomaterials in Lasers
· Nanomaterials in Fuel Cells and Photovoltaic Cells
· Nano communication and networks
· Nanosensors
RECENT DEVELOPMENT IN THE FIELD
“Nanotechnology enabling Wearable Technology”
Smartwatches, fitness trackers, smart clothing, smart medical attachments, data gloves — the market for wearable electronics is quickly evolving beyond health care, fitness, and wellness into infotainment and commercial and industrial applications. Wearable electronics consist of several areas: sensors, actuators, electronics, and power supply or generation. Whereas the first generation consisted mostly of detachable components, the second generation is moving towards textile-embedded sensors, actuators, and therapeutic solutions. One of the key challenges is the requirement to achieve and combine different properties like flexibility, user comfort, and the ability for the device to be miniaturized and fashionable. To do this, researchers are making use of different materials like carbon nanotubes, graphene, polymers, and dielectric elastomers and composites. These are tailored to specific applications depending on their different characteristic behaviors upon different stimuli.
Wearable actuators
Actuators react to an electrical signal or stimuli generated from a processing unit or a signal directly fetched from a sensor. Recent development has heating elements embedded in wearables; nanocomposite-based therapeutic devices; artificial muscles and muscular actuators; rehabilitation devices; and wearable drug delivery systems. To be incorporated into wearable and flexible electronics, the selection of material is very important. Traditional transducer materials like piezoelectric materials, magnetostrictive materials, and quantum tunneling composites are very hard to integrate into flexible materials due to their poor flexibility. This has led to the exploration of different material groups and the development of novel nanocomposites and other materials including metal nanoparticles, electroactive polymers, conductive polymers, ionic liquids, carbon nanotubes, graphene, and shape memory alloys. With this variety of materials and their applications, researchers have followed different fabrication processes as well including electrospinning, spray coating, knitting, weaving, and solution casting.
Wearable Sensors
Nanomaterial sensors sense an external stimulus and convert it into a measurable signal, which can later be transferred to a processing unit or a monitoring device. Wearable sensors are expected to be the most practicable and prospective applications in the near future. Wearable devices equipped with a series of simplified sensors such as temperature, strain sensors for posture and body movement, biosensors for disease monitoring, and multifunctional sensors for voice and facial expression detection can feed real-time data to a processing and monitoring central system. Wearable sensors need to be lightweight and flexible, exhibit superior mechanical and thermal performances to prevent them from being damaged and should be low cost. 1D nanomaterials and nanocomposites including metallic nanowires and nanofibers are being extensively used.
Nanomaterial-based sensors are mainly prepared by incorporating nanomaterials into flexible or elastic substrates such as fiber, fabric, or polymer matrix. To fabricate wearable nanomaterial-based sensors, researchers predominantly use spin coating, spray coating, drop-casting, dip coating, layer-by-layer assembly, vacuum filtration, and direct printing or writing techniques. These wearable sensors can be placed on or embedded in clothes or attached to parts of the body like the finger, wrist, arm, throat, chest, and leg. Others can be embedded into wearing accessories such as gloves, watches, earrings, necklaces, brooches, and so on.
The field of nanoelectronics has been slowly growing in recent years and is the answer to the increasing demand for electronics to be smaller, yet still, maintain a high performance. Nanomaterial-based components can be made much smaller than those made of traditional bulkier materials, which helps to reduce the overall size of the electronic device. Moreover, many nanomaterial are stable in most environments, whether it’s in a sensor within a harsh chemical processing environment, or in an electronic device that gives out a lot of residual heat to the internal components. While there are many areas of nanoelectronics, some of the more widely studied systems include nanomaterial-inspired energy storage and energy generation systems, various types of nanosized and molecular transistors, optoelectronic devices, and flexible/printable circuits where the nanomaterials are often formulated into an ink and printed.
Future applications will most likely include various quantum technologies if they can be realized on a commercial level, and we are likely to see an increase in the production of smaller components for classic computing systems and everyday technologies.
Thank you for reading!