Scientists seek to create ultra-thin keyboards that absorb light

Experts from the Russian National Nuclear Research University MEPhI have created a series of multi-layer ultra-thin film tables that can provide the basis for future electronics and energy.

The results were achieved through studies that elucidated the conditions of the heat synthesis of catabolism structures based on metal conversion dichalcogenides (TMDCs) MoS2, WS2, MoSe2 and WSe2.

Ultra-thin film tables of disulfide and diselenides of transition metals (for example, molybdenum and tungsten) have a rather efficient absorption of light. The reason for this is that the crystals of TMDCs are very small in size so the absorption of light can take place without the participation of phonon - network vibrations.

At the same time, nanocrystals can create conditions to separate water molecules into hydrogen and oxygen.Thus ultra-thin TMDCs film tables have a promising prospect in photochemical catalytic reactions as well as to create many modern optoelectronic devices - from photodetectors to photoelectric converters.

Ultra-thin film table of disulfide and diselenides have a characteristic of absorbing light quite effectively.

"It is important to create multi-layer film tables by defining the necessary conditions so that all TMDCs do not cause damage to the thin film with another previously applied TMDCs material . We have study conditions for creating high-quality ultrathin TMDCs membranes by heat treatment of metal thin film precursors and Mo and W metal oxides in sulfur or selenium vapors, as well as in hydrogen sulfide gas " , engineer Dmitry Fominsky from MEPhI University, specializing in thin-film laser deposition and nanostructures, told Sputnik.

According to him, those film tables have been studied using modern methods: scanning electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy. Research results show that the process of turning exchanging film tables containing Mo in sulfur vapors or hydrogen sulfide depends on the chemical state of the original "precursor" , produced by laser pulse deposition.

The use of laser pulse deposition allows the creation of a "sheet workpiece" of a film table with a certain thickness and chemical composition. That helped scientists determine the necessary conditions for effective sulfide conversion of Mo and MoOx films to create ultra-thin film tables MoS2 at temperatures below 500 ° C.

"We have also created film tables from transition metals, for example, diselenide tungsten layers, with perfect 2H lattices. The results of the study allow the creation of Mo-thin super-thin semiconductor films (W). SxSe2-x, has useful properties adjusted by metal concentrations (W / Mo) and chalcogens (S / Se), " said expert Dmitry Fominsky.

The group of scientists published the results of the study at the 16th International Conference "New Materials: High Endurance Nuclear Fuel". They note that the technological and temperature conditions for tungsten molybdenum sulfide and selenide formation are very similar. However, according to University of MEPhI experts, if using precursors (metals, metal oxides) and active means containing chalcogen, it is possible to select the necessary conditions to create the super film table. thin with specific chemical and structural properties.

Because film tables can act as optical catalysts - in the future this invention will help extract more efficiently the solar fuel components (hydrogen and oxygen) from water, without using expensive materials. money in platinum group metals.