A team of Hong Kong-led scientists have developed a new way to produce a semiconducting nanomaterial they say can be made into sensors on curved surfaces to create safer infrastructure and advance flexible wearable electronics. The nanomesh – formed from a network of nanowires – could be manufactured at much lower temperatures than existing semiconductors and grown on common materials such as plastic and paper, reducing production costs. The team from City University of Hong Kong, the Changchun Institute of Optics, Fine Mechanics and Physics at the Chinese Academy of Sciences (CAS), the University of Electronic Science and Technology of China, Zhengzhou University, Beijing University of Technology, and Kyushu University in Japan, published their findings in the peer-reviewed journal Nature Communications in April.
Semiconductors are silicon-based devices made up of hundreds of millions, and in some cases billions, of transistors, which act as tiny “switches” to control the movement of electrons. A semiconductor conducts electricity under some conditions but not others, making it a good medium to control electrical current. Most of the world’s semiconductors, also known as integrated circuits or microchips, are made from pure elements such as silicon extracted from sand.
In the recent study, the researchers used tellurium, an emerging semiconductor material. The element is semi-metallic – it can be controlled to act as a metal or semiconductor. It can be mixed with other metals to form alloys. Lead author Johnny Ho Chung-yin, Professor in the Department of Materials Science and Engineering at CityU, said tellurium had a unique structure made up of spiral chains of atoms bonded by van der Waals forces. The force enables tellurium nanomeshes to self-weld and grow on rigid, flexible or curved surfaces. The self-welding process boosts the performance and mechanical robustness of electrical devices, according to the study. “Thanks to van der Waals forces, we can grow the nanomesh on any substrate without worrying about defects in the material that could arise from being grown on an unsuitable substrate,” Ho said. To create the nanomesh, the team first vaporized tellurium source powder and applied them to a base material, such as silicon oxide, polymers or paper, where they were heated at 100 degrees Celsius and grew. The temperature is far lower than the required 600 to 700 degrees using conventional methods.
Ho said the nanomaterial was promising for applications in the Internet of Things (IoT) – the network of physical objects embedded with sensors, software and other technology to collect and share data, the South China Morning Post reports.
