Bench Talk

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Electronic devices, and the components within them, are getting smaller year by year. This has been driven by consumer demand for smaller devices that have the same capabilities and performance, if not better, than the pre-existing ‘bulkier’ technology. Here, we will explore in more detail how nanoelectronics not only reduce the size of electronic devices, but also provide the same or enhanced performance.

The Introduction of Nanoelectronics

Traditional materials can only go so far before they reach a point where they can’t get any smaller. This is where nanotechnology comes in and has enabled the field of nanoelectronics to emerge―which is when electronic components created using nanomaterials and are a fraction of the size of components made from conventional ‘bulk’ materials. One example of a nanoelectronic device is a graphene-based battery. This is a bulk device that uses nanomaterials, but compared to lithium ion (Li-ion) batteries, it can possess up to 5-6 times the energy density and still be smaller than their Li-ion equivalents. Another example―focusing purely on nanosized electronic components―are transistors made out of carbon nanotubes. Such small transistors push beyond the limits of conventional technology and because they are so small (yet efficient enough to function well) more transistors can be fitted onto circuits and computer chips, increasing the speed of devices.

The use of nanomaterials―i.e., materials which are between 1 and 100 nanometers in size―has many advantages. Not only are nanomaterials inherently small (often very thin), which can help to make the components of a device smaller (which can help to reduce the size of the device itself), they are usually very efficient. Because of their small size, they have a very high relative surface area, which in many cases is very active―with the best example of an active surface being graphene. Graphene’s surface interacts very strongly with its surroundings, be it through the conduction of electrons between surfaces or the interaction with environmental stimulus/molecules in sensing mechanisms, among others.

Most nanoelectronic devices are developed using either 2D materials or semiconductors, which are very active materials. Due to these properties, nanomaterials can provide electrical efficiencies as high, if not higher, than the bulk materials used in traditional components, but with the added bonus of being much smaller. This is especially true for conductive or semi-conductive nanomaterials that often have electrical conductivities and charge carrier mobilities—and more efficient junctions in the case of semiconductors—which are much higher than bulk materials. In addition, many nanomaterials are inherently stable to high temperatures, pressure and chemicals, which are often needed depending on the components in question—with thermal stability being very important for when devices get hot.

But it is not only the conductive nanomaterials that are efficient. While electrically conducting nanomaterials get the most attention, there are also plenty of electrically insulating nanomaterials than can be just as important for protecting certain areas of a nanoelectronic device. In fact, in some cases, heterostructures composed of sandwiching a conductive nanomaterial layer between two insulating nanomaterial layers works better, because the conductivity—and the subsequent electrical current—can be better directed (which results in a lower electrical energy loss). Other properties of nanomaterials include their ability to realize and utilize quantum phenomena, which can lead to more effective electronic currents as there is little to no resistance when the electrons travel between quantumly confined regions. These phenomena are also the building blocks for what will hopefully be the next generation of technologies, i.e., quantum technologies. So, there is a wide range of materials, with varying properties that can be used.

Aside from the property benefits, the way nanomaterials are fabricated enables the development of smaller components. Most non-nanomaterial components have to be fabricated using a top-down approach, which is when a larger material is broken down into smaller structures. But there are limits to how small you can go if the structural accuracy is to be maintained, especially if it is a complex architecture. Nanomaterials can also be made in this way, but if you want to have nanomaterials that are structurally accurate, pure, and very small, then they can be made using a bottom-up approach, which is the process of creating nanomaterials atom by atom. It is a more controlled approach that enables the size of the components to be reduced, while the active nanomaterials are pure and architecturally designed to fit their specific application. In many cases, both methods can be used together, to first create the thin nanoelectronics components through a bottom-up approach, followed by patterning it with a top-down etching or lithography approach.

So, what falls into the scope of nanoelectronics? Aside from being a smaller version of electronics, it encompasses everything from nanoscale components, to quantum technology, spintronics, and molecular electronics (i.e., single molecule electronics). In terms of the actual individual components that are present within the sphere of nanoelectronics, there are many, as nanoelectronics covers everything from energy storage and energy generation systems, to transistors, to flexible and printable circuits, switches, photodetectors, sensors, displays, memory storage systems, nanosized radio transmitters, and quantum devices—and there are many more in between, these are just the most notable components.

All these devices are made up of different nanomaterials, and the same components can be made with very different nanomaterials depending on the desired efficiencies, ease of fabrication, and cost. It’s also safe to say that nanoelectronics makes use of most nanomaterial forms, from 2D materials and other thin-film layers, to nanotubes, fullerenes, nanowires, nanoparticles, and quantum dots.

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 nanomaterials 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.