Associate Professor Nobuyuki Aoki of Chiba University is one of the most important values that determine the properties of semiconductors by simply irradiating molybdenum disulfide (MoS2), which is a kind of atomic layer material, with an electron beam with a scanning electron microscope (SEM). He announced that he discovered for the first time in the world the phenomenon that a certain band gap becomes large, and found that the properties of semiconductors can be easily controlled. Collaborative research with Professor JP Bird of SUNY Buffalo University and Professor R. Vajtai of Rice University.
Current large-scale integrated circuits (LSIs) made of silicon have improved their performance by making the transistors smaller and increasing the degree of integration.However, the method is approaching its limit, and instead of silicon, transistors made of one atomic layer made of atomic layer materials such as graphene and MoS2 are attracting attention.On the other hand, the value of the important characteristic bandgap that determines the performance of semiconductors is fixed for each substance and cannot be changed with conventional materials.
This time, the research group discovered that there are parts with different properties in a transistor made of a single layer of MoS1 single crystal.When we proceeded with the analysis using a scanning probe microscope in combination, it was found that the band gap was widened in the parts with different properties, and the boundary with the different properties affects the way of operation as a transistor. ..Further verification revealed that the cause of the change was the electron beam irradiation used in the electron beam lithography used in the material preparation process.From this, it was found that the band gap can be easily controlled by irradiating the atomic layer material with an electron beam with a simple device such as SEM.
In the future, by combining with bandgap control, it is expected that not only computers and memories but also various electronics such as LEDs and lasers can be realized only with atomic layer materials.
