Nanoelectronics, based on nanotechnology, is the next evolution of microelectronics, in which new devices will be designed at the nanoscale, at an atomic or molecular level. It is expected that this technology will enable the implementation of new molecular and quantum computing systems superior to any current supercomputer, allowing future electronic devices to be smaller than a matchbox and no larger than a grain of sand. These new computer systems will be much more powerful and faster, with virtually unlimited data storage capacity, reduced energy consumption, and lower operating costs. This makes nanoelectronics attractive to the nanotechnology industry.
What is Nanoelectronics?
Nanoelectronics refers to the use of nanotechnology in electronic components, especially transistors. Although the term nanotechnology is often defined as the use of technology smaller than 100 nm, nanoelectronics typically refers to transistor devices so small that it is necessary to thoroughly study interatomic interactions and quantum mechanical properties.
Approaches to nanoelectronics
Nanofabrication
For example, single-electron transistors, which involve transistor operation based on a single electron. Nanoelectromechanical systems also fall into this category. Nanofabrication can be used to build ultradense parallel assemblies of nanowires, as an alternative to synthesizing individual nanowires.
Nanomaterials electronics
In addition to being small and allowing more transistors to be placed on a single chip, the uniform and symmetrical structure of nanotubes allows for greater electron mobility (faster movement of electrons in the material), a higher dielectric constant (faster frequency), and a symmetrical electron/hole characteristic.
In addition, nanoparticles can be used as quantum dots.
Molecular electronics
Single-molecule devices are another possibility. These schemes would make extensive use of molecular self-assembly, designing device components to build a larger structure or even a complete system on their own. This could be very useful for reconfigurable computing and could even completely replace current FPGA technology. Molecular electronics is a new technology still in its infancy, but it also offers hope for the future of truly electronic systems at the atomic scale. One of the most promising applications of molecular electronics was proposed by IBM researcher Ari Aviram and theoretical chemist Mark Ratner in their work “Molecules for Memory, Logic and Amplification,” published in 1974 and 1988. This is one of many possible ways to synthesize a diode/transistor at the molecular level using organic chemistry. A model system was proposed with a spirocarbon structure that yields a molecular diode approximately half a nanometer in diameter, which could be connected using polythiophene molecular wires. Theoretical calculations showed that, in principle, the design was correct, and there is still hope that the system will work.
Other approaches
Nanoionics studies the transport of ions instead of electrons in nanoscale systems. Nanophotonics studies the behavior of light at the nanoscale and aims to develop devices that take advantage of this behavior.
Nanoelectronic Devices
Current high-tech production processes rely on traditional top-down strategies, into which nanotechnology has already quietly been introduced. The critical length scale for integrated circuits is already at the nanoscale (50 nm and less) relative to the gate length of transistors in CPUs or DRAM devices .
omputers
Nanoelectronics promises to make computer processors more powerful than is possible with conventional semiconductor fabrication techniques. Several approaches are currently being investigated, including new forms of nanolithography, as well as the use of nanomaterials such as nanowires or small molecules instead of traditional CMOS components. Field-effect transistors have been fabricated using both semiconducting carbon nanotubes and heterostructured semiconducting nanowires.
Energy production
Research is underway to use nanowires and other nanostructured materials in the hope of creating cheaper and more efficient solar cells than those made with conventional flat silicon solar cells. It is believed that the invention of more efficient solar energy would have a major impact on meeting global energy needs.
Research is also being conducted on energy production for devices that would operate in vivo, called bio-nanogenerators.
Medical diagnosis
There is great interest in building nanoelectronic devices that can detect the concentrations of biomolecules in real time for use in medical diagnostics, thus falling into the category of nanomedicine. A parallel line of research seeks to create nanoelectronic devices that can interact with individual cells for use in basic biological research. These devices are called nanosensors.
Spintronics
In addition to transistors, nanoelectronic devices play an important role in data storage (memory). In this field, spintronics—the study and exploitation in solid-state devices of electron spin and its associated magnetic moment, along with electric charge—is already a well-established technology.
Spintronics also plays a role in new technologies that harness quantum behavior for computing.
New optoelectronic devices
In modern communication technology, traditional analog electrical devices are increasingly being replaced by optical or optoelectronic devices due to their enormous bandwidth and capacity, respectively. Two promising examples are photonic crystals and quantum dots. Photonic crystals are materials with a periodically varying refractive index and a lattice constant that is half the wavelength of the light used. They offer a selectable band gap for the propagation of a specific wavelength, thus resembling a semiconductor, but for light or photons instead of electrons. Quantum dots are nanoscale objects that can be used, among many other things, to build lasers. The advantage of a quantum dot laser over a traditional semiconductor laser is that its emitted wavelength depends on the dot diameter. Quantum dot lasers are cheaper and offer higher beam quality than conventional laser diodes .
Sceens
Low-power displays can be produced using carbon nanotubes (CNTs) and/or silicon nanowires. These nanostructures are electrically conductive and, due to their small diameter of several nanometers, can be used as highly efficient field emitters for field-emitting displays (FEDs). The operating principle is similar to that of a cathode ray tube, but on a much smaller length scale.
Quantum computers
Entirely new computing methods leverage the laws of quantum mechanics to create innovative quantum computers that enable the use of fast quantum algorithms. A quantum computer has a memory space of quantum bits called a “qubit” to perform multiple calculations simultaneously. In nanoelectronic devices, the qubit is encoded by the spin quantum state of one or more electrons. The spin is confined by a semiconductor quantum dot or a dopant.
Radios
Structured nanoradii have been developed around carbon nanotubes.
Portable and Flexible Electronics
The era of wearable electronics has arrived, as evidenced by the rapid growth of smartwatches, fitness trackers, and other advanced, next-generation health monitoring devices, such as adhesive electronic tattoos. If current research is any indication, wearable electronics will go far beyond tiny electronic devices or wearable flexible computers. These devices will not only be integrated into textile substrates, but an electronic device or system could eventually become the fabric itself. Electronic textiles (e-textiles) will enable the design and production of a new generation of garments with distributed sensors and electronic functions. These e-textiles will have the revolutionary ability to sense, act, store, emit, and move—think of biomedical control functions or new human-machine interfaces—ideally leveraging an existing low-cost textile manufacturing infrastructure.
Conclusion
The field of nanoelectronics has been growing steadily in recent years and is the answer to the increasing demand for smaller electronic devices that still maintain high performance. Components based on nanomaterials can be made much smaller than those made with bulkier, traditional materials, helping to reduce the overall size of the electronic device. Furthermore, many nanomaterials are stable in most environments, whether in a sensor within a harsh chemical processing environment, or in an electronic device that emits a lot of waste heat to internal components. While there are many areas of nanoelectronics, some of the most widely studied systems include nanomaterial-inspired energy storage and generation systems, various types of molecular and nanometer-sized transistors, optoelectronic devices, and flexible/printable circuits, in which nanomaterials are typically formulated into an ink and printed. It is very likely that future applications will include various quantum technologies if they can be realized commercially, and we are likely to see an increase in the production of smaller components for classical computer systems and everyday technologies.