In situ growth optimization of 2D chalcogenides based on transition metals
Monolayer and few-layer materials are of great interest for chemical research due to their intriguing properties, such as high electrical conductivity, robust and protected quantum states, and strongly reduced thermal conductivity. In particular, the electronic and chemical properties of monolayer materials are of great interest for electrochemical and electronic applications, either to build high-capacity energy storage systems or electronic/photonic devices. Graphene and several other 2D materials, e.g. silicene, phosphorene and metal dichalcogenide monolayers, can be synthesised, modified and assembled together to form new materials and structures with greatly enhanced functionalities. Ultrathin 2D layered transition metal dichalcogenides such as MoS2 and WS2 are promising family of two-dimensional system that goes beyond graphene for next generation nanoelectronics. Inspiring 2D TMD devices, such as MoS2 transistors showing excellent performance, have been obtained using nanoflakes mechanically exfoliated from bulk geological samples. However, while the exfoliation approach is valuable for demonstrating the promise of 2D TMDs devices, it is not suitable for device production where repeatable and uniform large area deposition is desirable.
The aim of this project is development of a facile chemical vapor deposition route for large area and high quality 2D transition metal dichalcogenides (TMDs) nanosheets growth. The growth conditions for 2D TMD will be optimized by environmental scanning electron microscope at the Fritz-Haber Institute, Berlin, Germany and by in situ micro-Raman spectroscopy and optical microscopy using homemade optical cell developed in our laboratory in collaboration with partners from Institute of Physics, Zagreb, Croatia.
The first phase of the project will include the investigation of the growth mechanism, crystal structure of those materials, and their electrical properties. The design and construction of 2D electronic and optoelectronic devices based on produced nanosheets is predicted in the second part of the project.
The project will include the use of, in situ chemical vapor deposition, environmental scanning electron microscopy (ESEM), surface analysis techniques, scanning probe microscopy techniques (AFM, STM), Raman spectroscopy, and electronic transport measurements. The obtained materials will be also characterized by TEM techniques to determine uniformity and crystal structure of obtained materials. In this project will be for the first time combined three individual in situ techniques (ESEM, optical microscopy and Raman spectroscopy) for study of 2D TMDs synthesis. Those techniques will provide much better understanding of growth of proposed 2D materials from nanoscale to macroscale (order of size, mm).