From "building houses" to "supporting bamboo shoots", Chinese scientists pioneered a new method for crystal preparation

▲The picture shows electronic and photonic integrated circuits based on two-dimensional crystals (picture from Reference News)

Author: Huang Yanhong, Huang Xianghong, Duan Yuechu

In the vast world of science and technology, every major breakthrough is like a bright star, lighting the way forward for mankind. Recently, Chinese scientists have made a breakthrough in the field of crystal materials, pioneering a new method for preparing crystals, which has brought new hope and possibilities to the fields of computers, communications, aviation, laser technology, etc.

Crystals, seemingly ordinary but extremely critical materials, play an indispensable role in modern technology. From the computers and mobile phones we use in daily life to high-end equipment such as aerospace equipment and laser weapons, crystals are a vital component. The traditional method of preparing large-sized crystals has always been to stack atoms layer by layer on the surface of small crystal particles "from bottom to top", just like "building a house", starting from the foundation and "laying bricks" layer by layer, and finally building it.

However, with the rapid development of science and technology, the limitations of traditional methods have become increasingly prominent. In the traditional crystal preparation process, the types and arrangements of atoms need to be strictly screened before they can be stacked and combined to form crystals. However, as the number of atoms continues to increase, the arrangement of atoms gradually becomes uncontrolled, and impurities and defects continue to accumulate, which seriously affects the purity and quality of the crystals and becomes a bottleneck restricting the development of related fields.

The picture shows the preparation of wafer-level two-dimensional crystals using the new method of "lattice mass transfer-interface growth" (picture from Reference News)

In order to break this dilemma, the Peking University research team conducted in-depth research and exploration, and finally created a new crystal preparation method for the first time in the world - "lattice mass transfer-interface growth". This method is like "pushing up bamboo shoots" that "pushing up against the upper structure", which brings a new idea and model for crystal growth.

Specifically, the Peking University research team first arranged atoms on the "foundation", that is, the centimeter-level metal surface to form the first layer of crystals. Then, the newly added atoms entered between the metal and the first layer of crystals, growing on top of the already formed crystal layer, and continuously forming new crystal layers. This unique growth method allows the crystal layer structure speed to reach 50 layers per minute, and the number of layers can reach up to 15,000 layers.

What is even more amazing is that the atomic arrangement of each layer of the crystal grown by this new method is completely parallel and precisely controllable, which effectively avoids the accumulation of defects and greatly improves the controllability of the crystal structure. Using this new method, the research team has successfully prepared seven high-quality two-dimensional crystals such as molybdenum sulfide, molybdenum selenide, and tungsten sulfide. The single layer thickness of these crystals is only 0.7 nanometers, which has better performance and broad application prospects than the currently widely used 5-10 nanometer silicon materials.

When these two-dimensional crystals are used as materials for transistors in integrated circuits, the integration of chips can be significantly improved. Imagine that on a chip the size of a fingernail, the density of transistors is greatly improved, and computing power will achieve a qualitative leap. This means that our electronic devices will become smaller, more efficient, and more powerful, providing solid hardware support for the development of cutting-edge technologies such as artificial intelligence, big data processing, and virtual reality.

In addition, these new crystals can also be used for frequency conversion control in the infrared band, providing new possibilities for the application of ultra-thin optical chips. In the future, we may be able to see thinner and more efficient optical devices, such as high-resolution cameras and advanced lidar, which will bring revolutionary changes to communications, medical treatment, autonomous driving and other fields.

This breakthrough was published online in Science magazine on July 5, attracting widespread attention and high praise from the international scientific community. It not only demonstrates the profound research strength and innovation ability of Chinese scientists in the field of crystal materials, but also injects new vitality into the research and development of global crystal materials.

This major innovative achievement of Chinese scientists once again proves that scientific and technological innovation is an important force in promoting the progress of human society. In the days to come, we have reason to believe that as this technology continues to improve and be promoted and applied, it will bring more convenience and surprises to our lives and make greater contributions to the development and progress of human society.

Let us applaud this outstanding achievement of our country's scientists, and look forward to them making more breakthrough results in future scientific research, and continuously contributing their wisdom and strength to realize the Chinese dream of the great rejuvenation of the Chinese nation and to promote human scientific and technological progress and the development of civilization!