US developed a defect-free semiconductor nanocrystalline film

Researchers at the Massachusetts Institute of Technology have developed electron-beam lithography and stripping processes to develop defect-free semiconductor nanocrystal films. This is a promising new material that can be widely applied and open up potentially key research areas. The report was published online in the recently published Nano Express magazine.

The size of semiconductor nanocrystals determines their electronic and optical properties. However, it is very difficult to form a film having a uniform structure by controlling the arrangement of the nanocrystals on the surface. Typical nanocrystalline films generally have cracks that limit their effectiveness, making it impossible for researchers to measure the basic properties of these materials.

The conductivity of the defect-free film produced this time is about 180 times that of the crack film made by the conventional method. Scientists say the manufacturing method can also be applied to silicon surfaces to make films that are 30 nanometers wide. The trick is to make the film structure uniform and adhere to the silicon dioxide pedestal. This can be achieved by covering the thin polymer layer on the surface before the nanocrystalline layer is deposited on the silicon surface. It is speculated that fine organic molecules on the surface of the nanocrystals can also help them bond to the polymer layer.

In the early stages of the research, the nanofilm produced by the researchers produced invisible infrared light. But the work based on this system is very monotonous, because each time fine-tuning requires a long time-consuming electron microscopy. When successfully acquiring semiconductor nanocrystal patterns that emit visible light, it means that the research team can greatly speed up the development of new technologies. Even if the nanofilm is lower than the resolution limit of the optical microscope, the nanocrystals can be used as a light source to make them visible.

Researchers say the nanocrystalline film can be used in a variety of applications. Because they can not only emit light, but also absorb light of multiple colors. This helps to create luminescent pixels on high-resolution display screens or to make new types of high-efficiency, broad-spectrum solar cells. At the same time, this material can also be used to develop high-sensitivity detectors for a small number of specific biomolecules, such as toxin screening systems or medical testing equipment. In addition, the success of this technology has also opened up new research on how electrons move within nanocrystalline films, which has long been regarded as a major problem in the academic world.