Why Future Looks Bright for Carbon Nanotubes

Carbon nanotubes, often abbreviated as CNTs, are very small allotropes of carbon, with dimensions in the range of few nanometers or lower, which have properties that make them very much suitable for a number of applications

It has an enormously high tensile strength and they have a very high electrical conductivity along with other advantages such as the ability to withstand high temperatures and other extreme conditions. 

As for physical strength, it has been shown that potentially they can reach a modulus up to 1TPa, which would put them much beyond the limits of steel or other high-toughness materials available today

However, such theoretical properties have not been fully achieved yet, with current production methods such as CVD or spinning being able to produce them with substantially lower strength properties. Currently carbon nanotube-based yarns have been demonstrated with strengths of 10 GPa but having defects in the structure bringing down such value to 1GPa in real world applications 

While the production of carbon nanotubes has so far proven expensive, they are making a slow but steady advance in many fields such as medicine, military, automotive field, in the construction and electronics business among others.

So far, they have been also successfully adopted in small quantities in carbon fibers for the production of tennis rackets, baseball bats, automobile parts and for other mission-critical tools where strength and light weight are needed.

The issue of high cost has been so far the stumbling block preventing widespread adoption of carbon nanotubes for a range of applications, but efforts made by some major players such as Arkema S.A., CNano Technology Ltd., Hyperion Catalysis International Inc., are driving prices down and this may further increase their adoption for new applications, such as adoption in the IC market or in the MEMS market.

For example, new potential applications in the IC market are most interesting as IC based on CNTs, also known as carbon nanotube field-effect transistors, have been demonstrated to operate at room temperature and being able to switch using only one electron. Since the year 2000, several IC components have been developed, such as: nanotube-based transistors, nanotube-based memory components, nanotube-based memory switches; density of such components, however, is not even remotely comparable to today silicon-based ICs. 

Another future big market for CNTs may be the solar market, as they have shown the interesting property of being able to absorb infra-red light and therefore being able to increase the efficiency of classic silicon-based solar cells.

Finally, they may have yet another potential application in hydrogen storage, as they have the property to allow molecules of condensed gases being stored inside a single walled CNT.

Geographically wise speaking, the major growth in year 2012 in their utilization has been in the Asia-Pacific and United States markets, due to an increase of number of applications in the electronics and other semiconductor markets.

As of today, main players in the CNTs market are Nanocyl S.A. of Belgium, Showa Denko K.K. of Japan in addition to the companies already mentioned above: Arkema of France, CNano Technology Ltd. and Hyperion Catalysis International Inc. of the US.

About the Author-

This article was written by Matteo Martini, author and CEO of Martini Tech, a company that provides nanoimprinting, PSS patterning, MOCVD deposition, sputtering, MEMS foundry, GaN wafer, GaN LED Technology and other microfabrication-related services. Please have a look at our blog.

The Ubiquitous MEMS

Micro-electro-mechanical systems, or MEMS, are present in almost every electronic system that we use daily. They can be found in smartphones, cameras, automobiles, and all other kinds of electronic gadgets. MEMS act as microscopic components that enable our devices to become smaller, faster and lighter.

MEMS were first used in the early 80s, one of their first applications was as ink-jet printer heads and as sensors: later on MEMS technology advanced and nowadays we see MEMS successfully applied in the medical, automotive, aerospace, entertainment and other fields.

The development of MEMS made possible the fabrication of very small devices. MEMS production became practical once semiconductor IC devices manufacturing became widespread and common. A modification of the traditional semiconductor fabrication technologies made possible MEMS production on large scale since the technologies and processes used in MEMS fabrication are very similar to those adopted in IC fabrication. MEMS are made of various materials such as silicon, polymers, ceramics, and metals and their processing requires several techniques, including deposition, patterning, etching, and dicing.

MEMS have many applications, but one of their most important uses involves their role as very small mechanical switches to control the flow of electricity. This apparently simple role is very significant as it is one of the fundamental principles around the actuators and sensors in modern electronics. Examples of these sensors and actuators that utilize MEMS switches are the head of the inkjet printer, the accelerometer in a smartphone, the gyroscope in a game console controller, and the sensor in the car that controls the airbag release

Essentially, MEMS work in the same way mechanical switches work, but have the advantage of being very small. Chris Keimel, a Process Development Engineer at GE, says that a switch can be made to work faster if it is smaller. The smaller the mass of the switch, the faster it can be moved. This is very important for a switch operating on the order of microseconds and it is essential for faster and more compact electronic devices.

A mechanical switch has a switch arm that moves to turn the flow of electricity on or off, MEMS also have a switch arm that is usually much thinner than a human hair and it would not be able to oscillate quickly as needed if it were thicker than that. Micro-switches speed is not limited by the laws of classical physics, such as inertia, but by other factors such as wetting and electrostatic forces. Their small size means that they can be accelerated further via electrostatic forces due to their relatively large surface areas.

Aside from acting as switches, the fast oscillation of MEMS is also utilized in other applications. Movie projectors that use digital light projection utilize thousands or hundreds of thousands of minuscule mirrors that oscillate at very fast rates. The oscillation rate can be controlled to adjust the intensity of the light reflected.

Given that the current technological trend is toward miniaturized, commoditized electronics systems, MEMS switches will continue to play a bigger role in technology advancement. While we may even not notice this revolution coming, the effects will be just under our eyes.

About the Author-

This article was written by Matteo Martini, author and CEO of Martini Tech, a company that provides nanoimprinting, PSS patterning, MOCVD deposition, sputtering, MEMS foundry, GaN wafer, GaN LED Technology and other microfabrication-related services. Please have a look at our blog.

There Is a Lot of Media Attention on 3D Printing Today, But It Has Not Been Always Like This.

Until few years ago, 3D printing was a niche technology used mostly for prototyping and creating models of small-size structures for some selected applications. For example, it was used, albeit not extensively, in producing small-scale models of buildings, mechanical parts, tools and other objects.

However, since the technology has been adapted to fit other applications as well, it has been possible to use 3D printing to actually create or even mass produce various components for the aerospace, consumer, healthcare, automotive and other industries. 

In other words, 3D printing has moved from the stage of technology for model prototyping to the stage of real-world manufacturing along with other classical technologies for mass production of components such as vacuum casting, injection and plastic molding and CNC-controlled lathing and machining.

While it is unlikely that 3D printing may supplant any of the above technologies anytime soon, many analysts agree that 3D printing has many advantages if compared to other classical methods of mass production such as a very high flexibility in the production mix and no or very few re-tooling requirements.

Flexibility in the production mix means that it is possible to 3D print many different shapes and forms using a variety of materials without any strong requirement of customization of the printing machine.

This allows the 3D printer to be able to produce everything from the single component to the small-lot production pre-series up to high-volume production

Flexibility in the production scale also means adaptability to be used in several different markets: in the aerospace and healthcare markets were low-volumes and customization of the product are in most cases a must.

Several players are active in the 3D printing arena: some of them are from Europe, such as EnvisionTec from Germany or LayerWise from Belgium, other are from the US, such as Organovo and ExOne.

Arcam of Sweden and Renishaw of the United Kingdom are also smaller players which are growing up fast to join the ranks of the big guys.

While 3D printing may seem a unique and well defined technology to many, it comprises a number of different methods of printing the final product: laser sintering and laminated object manufacturing being some of them, along with stereo-lithography and electron-beam melting

Desktop inkjet printing is also needful for very small-scale, lab sized applications, where very few pieces need to be manufactured at low cost for research or product development applications.

Other market segments where 3D printing is expected to become widely adopted are small-variety large-lot production markets such as the automotive and architecture markets. While there is still a huge gap in what dimensionally can be printed today and the size of what would be needed to print in the architecture market, that is, a portion of building or an entire chassis of a car, there are no inherent limitations in the technology that would prevent the creation of very large 3D printing machines capable of 3D printing virtually any other object which is mass produced today by other means.

About the Author-

This article was written by Matteo Martini, author and CEO of Martini Tech, a company that provides nanoimprint, PSS patterning, MOCVD deposition, sputtering, MEMS foundry, GaN wafer, GaN LED Technology and other microfabrication-related services. Please have a look at our blog.

Why gallium nitride is becoming increasingly popular?

Gallium nitride is becoming increasing popular as a replacement to silicon for many applications in different markets: opto-electronics such as LEDs, ICT and power electronics among others.

One of the major areas where GaN is already today utilized with success is the market of opto-electronics and LEDs.

LEDs (or light emitting diodes) are semiconductor-based devices that are slowly but steadily replacing the traditional incandescent bulbs in applications such as indoor and outdoor illumination, TV screens and monitors (also using OLEDs, or organic light emitting diodes, and other kinds of LEDs) among others due to their lower power utilization and to their high lifetime which comes from the advantage that they do not need to be replaced due to filament burn out and other problems typical of traditional incandescent light bulbs.   

Currently, GaN is deposited over patterned sapphire substrates (also known as PSSs) to improve the efficiency and light output, but recent research seems to point to an improvement in the overall conditions by deposition of a thin film of GaN directly on silicon substrates therefore reducing the costs of production, since silicon is a material already widely used in electronics and therefore production and patterning of silicon wafers does not require to buy new equipment and tools.   

The main advantage of GaN-deposited substrates compared with traditional non-sputtered LEDs is higher brightness.   

Besides the LED and opto-electronics industry, another major application of GaN-deposited substrates is in the power electronics, mainly in the automobile industry and in the aerospace and satellite industries.

GaN-deposited substrates are already commonly used in applications such as power amplifiers, power supply units, rectifiers, switchers, inverters RF devices and are quickly replacing traditional silicon-based devices such as FETs, HEMTs, Schotty diodes among others due to much higher breakdown voltage, higher conductivity and larger band gap therefore offering improved performance and better reliability.   

HEMT is a kind of power IC which is crucial in many applications in the aerospace and other businesses.

HEMT is a type of field-effect transistor device which is focused on high-frequency tasks and usage of GaN leads to a higher electron mobility and breakdown voltage if compared with traditional materials such as silicon and gallium arsenide

Finally, other applications of GaN-based devices are in the automotive sector and in the solar market: hybrid and electric vehicles make heavy use of GaN-powered technology.

In the solar and other renewables market (mainly wind), the most popular and widely used GaN-based devices are: Smart Grid Power Devices, High-Voltage Direct Current (HVDC) units, power systems for wind turbines and solar grids among others

Finally, in the communication industry GaN-based devices are found in radars, satellite communication systems, mainly due to the possibility to work at high-frequency ranges   

From the consumer and from the final user point of view, GaN-powered devices are more compact and more resistant to shocks than their silicon-based counterparts.

As of today, GaN-based power semiconductors account for about 1% of the total market (currently valued at around $40 billion) but they are growing very fast and they are expected to take a larger share of the business within 5 to 10 years potentially supplanting their traditional silicon-based counterparts in the long term.

About the Author-

This article was written by Matteo Martini, author and CEO of Martini Tech, a company that provides nanoimprint, PSS patterning, MOCVD deposition, sputtering, MEMS foundry, GaN wafer, GaN LED Technology and other microfabrication-related services. Please have a look at our blog.