In recent years, attention has focused on the physical properties of monoatomic films with a thickness of one atom and thin films with a thickness of several atoms. In order to realize the applications of 2D materials in the field of electronics, there has been demand for a technique capable of direct synthesis of various high-quality monoatomic films on any substrates.

The researcher, in collaboration with Nanyang Technological University of Singapore, has developed a simple synthesis method to grow a monoatomic film of transition metal chalcogenide on a substrate as a 2D material.

The developed synthesis method uses chemical vapor deposition (CVD). By adding salts (NaCl, KI) to a transition metal source and melting it, then supplying a chalcogen source with a carrier gas, it can directly synthesize and grow monoatomic films of various transition metal chalcogenides, which have been difficult to produce until now, on a silicon substrate. The researcher synthesized 47 types of transition metal chalcogenide monatomic films, including niobium diselenide, which exhibits superconducting properties. Using the advanced electron microscopy technology of AIST, the synthesized 2D materials were found to be high quality with few defects and impurities. The monoatomic films developed by the synthesis method may be applicable to many electronic devices such as field effect transistors (FETs) and diodes, and is expected to contribute to the nanoelectronics field in the future.