Researchers at Chalmers University of Technology have developed a method for efficiently cooling electronics using graphene-based film ("Improved Heat Spreading Performance of Functionalized Graphene in Microelectronic Device Application"). The film has a thermal conductivity capacity that is four times that of copper. Moreover, the graphene film is attachable to electronic components made of silicon, which favours the film's performance compared to typical graphene characteristics shown in previous, similar experiments. Electronic systems available today accumulate a great deal of heat, mostly due to the ever-increasing demand on functionality. Getting rid of excess heat in efficient ways is imperative to prolonging electronic lifespan, and would also lead to a considerable reduction in energy usage. According to an American study, approximately half the energy required to run computer servers, is used for cooling purposes alone. 
This is graphene-based film on an electronic component with high heat intensity. (Photo: Johan Liu / Chalmers University of Technology) A couple of years ago, a research team led by Johan Liu, professor at Chalmers University of Technology, were the first to show that graphene can have a cooling effect on silicon-based electronics. That was the starting point for researchers conducting research on the cooling of silicon-based electronics using graphene. "But the methods that have been in place so far have presented the researchers with problems", Johan Liu says. "It has become evident that those methods cannot be used to rid electronic devices off great amounts of heat, because they have consisted only of a few layers of thermal conductive atoms. When you try to add more layers of graphene, another problem arises, a problem with adhesiveness. After having increased the amount of layers, the graphene no longer will adhere to the surface, since the adhesion is held together only by weak van der Waals bonds." "We have now solved this problem by managing to create strong covalent bonds between the graphene film and the surface, which is an electronic component made of silicon," he continues. The stronger bonds result from so-called functionalisation of the graphene, i.e. the addition of a property-altering molecule. Having tested several different additives, the Chalmers researchers concluded that an addition of (3-Aminopropyl) triethoxysilane (APTES) molecules has the most desired effect. When heated and put through hydrolysis, it creates so-called silane bonds between the graphene and the electronic component (see picture). Moreover, functionalisation using silane coupling doubles the thermal conductivity of the graphene. The researchers have shown that the in-plane thermal conductivity of the graphene-based film, with 20 micrometer thickness, can reach a thermal conductivity value of 1600 W/mK, which is four times that of copper. "Increased thermal capacity could lead to several new applications for graphene," says Johan Liu. "One example is the integration of graphene-based film into microelectronic devices and systems, such as highly efficient Light Emitting Diodes (LEDs), lasers and radio frequency components for cooling purposes. Graphene-based film could also pave the way for faster, smaller, more energy efficient, sustainable high power electronics."
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This is graphene-based film on an electronic component with high heat intensity. (Photo: Johan Liu / Chalmers University of Technology) A couple of years ago, a research team led by Johan Liu, professor at Chalmers University of Technology, were the first to show that graphene can have a cooling effect on silicon-based electronics. That was the starting point for researchers conducting research on the cooling of silicon-based electronics using graphene. "But the methods that have been in place so far have presented the researchers with problems", Johan Liu says. "It has become evident that those methods cannot be used to rid electronic devices off great amounts of heat, because they have consisted only of a few layers of thermal conductive atoms. When you try to add more layers of graphene, another problem arises, a problem with adhesiveness. After having increased the amount of layers, the graphene no longer will adhere to the surface, since the adhesion is held together only by weak van der Waals bonds." "We have now solved this problem by managing to create strong covalent bonds between the graphene film and the surface, which is an electronic component made of silicon," he continues. The stronger bonds result from so-called functionalisation of the graphene, i.e. the addition of a property-altering molecule. Having tested several different additives, the Chalmers researchers concluded that an addition of (3-Aminopropyl) triethoxysilane (APTES) molecules has the most desired effect. When heated and put through hydrolysis, it creates so-called silane bonds between the graphene and the electronic component (see picture). Moreover, functionalisation using silane coupling doubles the thermal conductivity of the graphene. The researchers have shown that the in-plane thermal conductivity of the graphene-based film, with 20 micrometer thickness, can reach a thermal conductivity value of 1600 W/mK, which is four times that of copper. "Increased thermal capacity could lead to several new applications for graphene," says Johan Liu. "One example is the integration of graphene-based film into microelectronic devices and systems, such as highly efficient Light Emitting Diodes (LEDs), lasers and radio frequency components for cooling purposes. Graphene-based film could also pave the way for faster, smaller, more energy efficient, sustainable high power electronics."
Close up of the 7nm node test chip. (Photo: Darryl Bautista) Working together, the team achieved an industry first–producing working test chips at New York’s SUNY NanoTech Complex near Albany whose smallest features approach 7 nanometers. As a result, the industry will be able to place more than 20 billion tiny switches on chips the size of a fingernail. The implications of our achievement are huge for the computer industry. By making the chips inside computers more powerful and more efficient, IBM and our partners will be able to produce the next generations of servers and storage systems for cloud computing, big data analytics and cognitive computing. With this feat by the alliance, we’re extending the life of the silicon semiconductor, one of the most important inventions of the 20th century, which has come to symbolize the seemingly inevitable march of technological progress–the ability to make all sorts of computers and electronic devices faster, smaller and more energy efficient. These advances represent the most significant chip-industry design and manufacturing innovations in nearly a decade. In recent years, the chip industry has struggled to sustain a torrid pace of semiconductor innovation. Each wave of miniaturization has come only through near-superhuman feats of creativity by scientists and engineers. IBM has played a critical role in many of these breakthroughs. For example, our scientists led the shift from aluminum wiring to copper to improve processing speeds; using Silicon on Insulator technology to reduce power consumption; and using High-k materials to reduce leakage of electrical current. We achieved the latest step improvement, called the “7 nm node” by the chip industry, through a combination of new materials, tools and techniques. In materials, we’re using silicon germanium for the first time in the channels on the chips that conduct electricity. We have employed a new type of lithography in the chip-making process, Extreme Ultraviolet, or EUV, which delivers order-of-magnitude improvements over today’s mainstream optical lithography. All told, we’ve made dozens of design and tooling improvements. It has been a massive effort requiring multiple breakthroughs in science, technology and chip architectures and manufacturing processes. 
7nm node transistors packed below 30nm fin pitch. (Image: IBM Research) Looking ahead, there’s no clear path to extend the life of the silicon semiconductor further into the future. The next major wave of progress, the 5 nm node, will be even more challenging than the 7 nm node has been. IBM has committed to spending $3 billion on chip research and development aimed at further extending today’s mainstream semiconductor technologies even while we’re exploring innovations that depart radically from the use of silicon as a primary material in semiconductors and the use of transistors for processing data. We’re targeting new kinds of materials and technologies such as silicon photonics, carbon nanotubes and graphene; as well as entirely new approaches to computing, including neuromorphic computing and quantum computing. Society is more than 50 years into the journey of silicon semiconductors, and, thanks to our work on the 7 nm node, the technology still has some runway. Now, we look further into the future and see the opportunity to reinvent computing. Science doesn’t get harder–or more satisfying–than this.
Student Elise Ramleth Østli and PhD candidate Federico Mazzola check their experiment. As part of her master's project at NTNU, Elise Ramleth Østli spent time in Stockholm, studying the tubes used with intravenous catheters. Back at NTNU, she contacted Justin Wells at the Department of Physics, asking if he was interested in continuing studies on these types of medical materials. Silver breaks down chemotherapy drugs “We wanted to find potential problem sources in the tubes used in intravenous catheters. An interaction between the coating and the drugs was one possibility. Chemotherapy drugs are active substances, so it isn’t hard to imagine that the medicine could react with the silver,” says Justin Wells, an associate professor of physics at NTNU. Wells and his students used x-ray photoemission spectroscopy (XPS) to look at the surface chemistry of one of the most commonly used chemotherapy drugs, 5-Fluorouracil (5-Fu), and the interaction between it and the type of silver coating found in medical equipment. Using an XPS instrument at the synchrotron lab MAX IV in Sweden, they found that the antibacterial silver coating actually breaks down the drugs. Not only does this reduce the effect of a chemotherapy treatment, but it also creates hydrogen fluoride, a gas that can be harmful both to the patients and to the medical equipment. “Reactions between chemotherapy drugs and other substances that the drugs come in contact with have, as far as we know, never been studied like this before,” Wells says. It has always been assumed that the drugs reach the body fully intact. The group continued their studies with the XPS instrument, now examining how the same chemotherapy drugs reacted with graphene. “Graphene is a non-reactive substance, and is sometimes referred to as a magical material that can solve any problem. So we thought that it might be a good combination with the chemotherapy drugs,” Wells explains. And they were right— the drugs did not react with the graphene. Graphene has already been suggested as a coating for medical equipment, and according to researchers, it should be possible to create thin layers of graphene designed for this use. “This research has produced valuable information about the interaction between chemotherapy drugs and other substances that the medicine is in contact with. We hope that our work will contribute to making cancer treatment more effective, and that we can continue our work in this area. We would like to study the reaction between chemotherapy drugs and other substances and coatings used on medical equipment,” Wells concludes.