A New Manufacturing Method May Pull Nanowires From the Research Realm to Market
Nanowires are seeing drastic advances in academia, emphasizing the promise that they offer the optoelectronics industry.
Back in 2013, MIT contributor David L. Chandler described nanowires as a "hot material" in the field. Additionally, All About Circuits covered advances in nanowires in 2016 when researchers recorded the formation of nanowires in real-time with an electron microscope and discovered organic nanowires for electronic devices.
While nanowires have continued to foster interest at research institutions, some key characteristics of the material have slowed its market adoption.
Nanowires are essentially solid crystalline fibers of either metals or semiconductors that have diameters on the order of nanometers (hence the name), but with lengths that are significantly longer. The effect is a “quasi-one-dimensional” material, offering desirable electrical and optical properties.
Transition metal chalcogenides nanowire structure. Image used courtesy of the American Chemical Society and SciTech Daily
In this article, we’ll take a look at why nanowires are so heavily researched, and a recent development that is pushing the technology closer to industry.
Due to the dimensions of a nanowire, carrier electrons or photons experience what is known as quantum confinement effects. This is why they're sometimes called "quantum wires." Semiconductors that experience these effects absorb photons at one wavelength but transmit them at another wavelength.
This has opened research possibilities for nanowires to be used in LEDs, solar cells, and many other optoelectronic devices.
An array of nanowires under an electron microscope. Image used courtesy of Kristian Molhave, MIT
While this spread of applications is impressive, it isn’t entirely unique; quantum dot technology also benefits from these effects. The difference with nanowires is that due to their great lengths (sometimes even visible by the human eye), nanowires can connect with devices on the macroscopic level.
Beyond this, another benefit of nanowires is that their structures make them impervious to manufacturing defects. Defects are classically an avoidable issue with crystalline semiconductor manufacturing.
An Improved Method to Manufacture Nanowires
This week, researchers at Tokyo Metropolitan University announced that they discovered ways to produce nanowires of transition metals at scale via chemical vapor deposition.
Using CVD, the researchers found that they could assemble nanowires in different arrangements depending on the substrate they’re grown on. Just by altering where the nanowires were grown, the researchers created centimeter-sized wafers with nanowires in their desired arrangement.
The CVD growth of tungsten ditelluride nanowires at a wafer-scale. Image used courtesy of Nano Letters
In addition, the technique yielded results that greatly matched theory as the wires were crystalline in nature and behaved much like one-dimensional materials. Researchers claim that this new method of manufacturing nanowires could make way for production at scale thanks to the familiarity manufacturing facilities already have with CVD.
Still a Research-Based Technology
While nanowires are a growing interest for optoelectronic engineers and material scientists, these structures are still largely in the research realm. Indeed, nanowires feature unique optical and electrical properties that could be useful in applications such as LEDs and solar cells, but as of yet, they have not been concretely adopted into the market.
The researchers at Tokyo Metropolitan University have high hopes that this step forward in manufacturing procedure could change that reality.