In this blog post, we’ll take a step-by-step look at the concept of nanotechnology, its development, key technologies, applications, future prospects, and limitations.
In the 1987 sci-fi film ‘Innerspace’, directed by Joe Dante, there’s a scene where the protagonist explores the inside of blood vessels aboard a minuscule airship. The concept of a mechanical device traveling through blood vessels was a highly innovative sci-fi plot device at the time, but today it is no longer a far-fetched notion. In fact, active research is underway to utilize ultra-small mechanical devices within blood vessels, and nanotechnology serves as the foundation for this technology. It is often said that the 21st century is the era of IT (Information Technology), BT (Biotechnology), and NT (Nanotechnology); nanotechnology has established itself as a core technology across various industrial sectors and continues to advance rapidly. However, despite its importance, most people do not fully understand nanotechnology. In this article, we will examine what nanotechnology is, explore its technical background and development process, categorize nanotechnology into sub-technologies to examine its application areas, and finally, look at the future of nanotechnology and the potential issues that may arise along the way.
Nanotechnology refers to the technology of synthesizing, assembling, and controlling materials at the extremely small scale of atoms or molecules, as well as measuring and elucidating their properties. The “small scale” referred to here generally means the range of 1 to 100 nanometers (nm). One nanometer is one-billionth of a meter, and the term “nano” is derived from the Greek word “nanos,” meaning “dwarf.” Considering that a human hair is about 80,000 to 100,000 nanometers thick, it is easy to understand just how small a scale nanotechnology operates on.
The concept of nanotechnology was first proposed by the American physicist Richard Feynman. In a 1959 lecture titled “There’s Plenty of Room at the Bottom” delivered at the American Physical Society, he predicted that an era would come when it would be possible to freely create extremely small structures even within the tiny spaces at the molecular level. As an example, he explained that the entire Britannica Encyclopedia could be recorded on a surface the size of a single hairpin. Since the level of technology at the time was not yet advanced enough to make this a reality, many attendees dismissed his claim as unrealistic.
The scanning tunneling microscope (STM), invented in 1981, was instrumental in transforming nanotechnology—which had previously seemed like science fiction—into a practical scientific and technological field. An STM is a device capable of observing or modifying the surface structure of semiconductors or conductive materials at the nanometer scale. It analyzes surface structures by bringing a probe with an extremely sharp tip close to the surface of an object, then applying a voltage between the probe and the object to measure the resulting current. The development of the STM went beyond simply observing material surfaces; it opened up the possibility of moving and arranging atoms and molecules. In 1986, five years after the invention of the STM, the atomic force microscope (AFM) was developed.
Unlike the STM, the AFM is a device in which the probe makes direct contact with the object’s surface to measure the degree of movement caused by the undulations of the atoms. Just as one would use a finger to feel the surface of an object and determine its shape, the AFM observes the surface by analyzing the probe’s movement. The development of the AFM made it possible to analyze even the surfaces of insulating materials, which were difficult to observe with the STM.
However, both the STM and the AFM had critical limitations. The biggest problem was that the process took far too much time. Using these devices, which could move only one atom or molecule at a time, to assemble materials visible to the naked eye was, in practical terms, a task requiring an enormous amount of time.
The person who proposed molecular-level machines as a solution to this problem was the American scientist Eric Drexler. In his 1986 book ‘Engines of Creation’, he argued that nanotechnology should be approached through the molecular machines found in nature. In the book, he explained that the ultimate goal of nanotechnology is to develop molecular-level machines—such as ribosomes—that use molecules as building blocks to assemble desired macroscopic structures. A ribosome is a complex of RNA and proteins that, within living organisms, combines amino acids to produce proteins based on genetic information. In other words, Drexler argued that we need molecular-scale machines—which, just as ribosomes synthesize proteins based on genetic information from DNA, would assemble molecules according to a preprogrammed sequence to produce desired materials—and he named these machines “assemblers.” However, an assembler of the form he proposed has not yet been realized, which means that modern science and technology have not yet reached the ultimate stage of nanotechnology he envisioned. Let us, then, examine how far current nanotechnology has advanced.
Generally, nanotechnology can be categorized into five sub-technologies based on technical difficulty. Specifically, these include technology for manufacturing nanomaterials; measurement technology for assessing the physical and chemical properties of nanoscale particles; technology for manipulating and integrating manufactured nanomaterials; application technology for nano-devices; and modeling and simulation technology.
The first category, nanomaterial fabrication technology, is further divided into two approaches. One is the top-down process, which involves gradually reducing the size of the material. This method processes existing materials down to the nanoscale, much like carving a large stone to make a spear or an axe. While this method has the advantage of allowing relatively easy fabrication of desired shapes, it has limitations when it comes to precision processing down to extremely small sizes. The other is the bottom-up process technology, which builds materials by combining atoms and molecules one by one. This method uses chemical reactions to assemble molecules sequentially, offering the advantage of creating very small structures; however, it has the disadvantage of making it difficult to maintain consistent quality and having a slow production speed, which is a drawback for mass production.
A prime example of bottom-up processing technology is the carbon nanotube (CNT). Carbon nanotubes are cylindrical carbon structures based on buckyballs (fullerenes)—carbon molecules shaped like soccer balls—and are currently being extensively researched and utilized across various industrial sectors. Carbon nanotubes are one of the most representative carbon structures, following diamond and graphite, and have a diameter of only about 1 nanometer. Thanks to their extremely small size and unique bonding structure, they possess tensile strength superior to that of steel and exhibit excellent electrical and thermal conductivity. Furthermore, depending on their structure, they can exhibit semiconductor properties, making them a promising candidate for next-generation semiconductor materials. Beyond this, they are being utilized in various fields such as flat-panel displays, batteries, composite materials, and biosensors, and ongoing research is being conducted.
Once nanomaterials have been produced using the top-down and bottom-up fabrication technologies discussed above, the next step is to develop technologies for manipulating and integrating these materials. However, what must be developed first is measurement technology capable of accurately measuring the properties of the fabricated nanomaterials. This is because, without sufficiently advanced measurement technology, it is impossible to accurately understand what phenomena occur at the nanoscale. However, a major obstacle exists in the development of nanoscale measurement technology: the fact that quantum effects emerge as the size of a material becomes extremely small. When quantum effects occur, it becomes difficult to explain phenomena using only the laws of physics applicable at everyday scales, making it challenging to accurately measure the properties of materials. Furthermore, as the size decreases, the measurement signal itself becomes very weak and is greatly affected by ambient noise, necessitating highly sensitive measurement equipment. For these reasons, nanometrology remains an area of active research today.
Technologies for manipulating and integrating nanomaterials are also areas that require further development in the future. Currently, precision manipulation and integration technologies are widely used at the micrometer scale—which is much larger than the nanoscale. A prime example is the semiconductor industry. The continuous improvement in semiconductor performance today is a result of advancements in these microfabrication technologies. If even more precise manipulation and integration at the nanometer level become possible in the future, the performance of various electronic devices, including semiconductors, is expected to improve significantly compared to current levels. Along with this, application technologies for nanodevices, as well as modeling and simulation technologies, are also expected to become more sophisticated based on advancements in measurement, manipulation, and integration technologies.
So, what will nanotechnology look like once these technical challenges are resolved? In his 1991 book ‘Unbounding the Future’, Eric Drexler identified computers, manufacturing, and medicine as fields with particularly high potential for future development. In the field of computing, he highlighted the advancement of bioelectronics as a key possibility. Bioelectronics is a convergent field combining biotechnology and electronics, with the development of biocomputers as one of its primary research goals. Although it is not yet clear exactly what form biocomputers will take, various studies are underway to overcome the limitations of existing silicon semiconductors by utilizing biomolecules such as proteins.
Biocomputers are just one example of future technologies enabled by nanotechnology. As nanotechnology advances further, manufacturing techniques that precisely control materials at the atomic level are likely to become even more sophisticated. While current manufacturing methods involve processing large numbers of atoms simultaneously to create products, the ability to design and assemble materials with precision at the atomic level is expected to enable the production of products that more closely match the original design intent. Furthermore, it is expected to significantly contribute to improving product quality and reliability, as well as to the development of materials and products with new properties that were previously difficult to achieve.
The medical field is also expected to be greatly influenced by nanotechnology. The field that combines nanotechnology and medicine is called nanomedicine. Since diseases in the human body often originate at the cellular and molecular levels, nanotechnology can play a crucial role in diagnosing and treating diseases with greater precision. In fact, research and clinical applications utilizing nanotechnology are actively underway in various fields, including drug delivery systems that selectively deliver drugs to specific sites, cancer treatment, tissue regeneration, and diagnostic technologies. It is expected that the development of even more sophisticated nanotechnology in the future will significantly improve the efficiency and safety of disease treatment.
Based on what we’ve discussed so far, the future appears to be brighter thanks to advances in nanotechnology. However, like other cutting-edge technologies, nanotechnology also has several negative aspects. Because nanoparticles are extremely small, they may exhibit properties different from those of ordinary particles when introduced into the human body. In fact, research findings have been reported indicating that some nanomaterials may enter the body through the respiratory tract or skin and potentially affect health; since the level of risk can vary depending on the type of material and the method of exposure, ongoing research and safety assessments are being conducted. Furthermore, concerns are consistently being raised regarding the potential for nanotechnology to be used for malicious purposes. Therefore, for nanotechnology to be utilized for the benefit of humanity, safety verification and ethical and social discussions must proceed in tandem with technological development.
We have examined nanotechnology from various perspectives thus far. Currently, not only the United States and other developed nations but also countries around the world, including South Korea, recognize nanotechnology as a key industry of the future and are continuing to invest heavily in research and development. South Korea, too, is continuously implementing national policies to foster nanotechnology and is strengthening its competitiveness in various industrial sectors, such as semiconductors, displays, rechargeable batteries, biotechnology, and advanced materials. As such, nanotechnology is advancing rapidly based on steady research and investment, and it is expected to continue playing a significant role in the natural sciences and across the industrial sector as a whole. Furthermore, as its scope of application expands across various industrial sectors, it will establish itself as a core technology that is even more closely intertwined with our daily lives.
