FEFU Young Scientists Developing Laser Equipment Materials

Ceramic heterostructures for optical and microelectronic devices will provide the supremacy in such fields like range findings, optical communications, data laser processing and recording. Work is carrying out under the grant support of the Russian foundation for basic research (RFBR).

Young scientists team of Far Eastern Federal University (FEFU) led by Denis Kosyanov, senior researcher, School of Natural Science, got RFBR grant funding for developing and standardization of manufacturing processes of the new materials based on "laser ceramic - thermoelectric" heterostructures. This project was highlighted as one of the best amidst interdisciplinary fundamental research projects in the field of "Ceramic materials for electronic and medicine".

RFBR grant is three year-long program. During this period, scientists will synthesize the basic nanopowders, establish sintering parameters of the laser-ceramic layer with a thermoelectric component, elaborate the method for their combination into unified material, and will standardize this material functionality and then put it into practice. For the producing of heterostructural ceramics the innovative method of reactive vacuum sintering will be applied. Yttrium-aluminum garnet YAG:RE3+ and strontium titanate SrTiO3?TiO2 were proposed as sintering components.

As Denis Kosyanov said, the methods, which his team apply in the frame on ceramic technologies, remove many principal restrictions, which are innate part of traditional methods of monocrystals growing for laser systems. Incorporating the laser environment with a thermoelectric, the combined ceramic structures will improve the performance characteristics of the final material in several ways. It includes the possibility of cooling the active laser medium - the so-called "active" way, and conversion of a part of thermal energy into electrical energy - the so-called "passive" way. As a result, a multiple reduction in thermal stress (in comparison with monolayer structures) will provide the high pumping efficiency, peak radiation power and material destruction threshold.

"The fundamental scientific task of the project is to establish the regularities of the joint sintering of laser and thermoelectric nanoceramics, which are different in terms of the crystal structure and phase composition. The task is further complicated by the fact that the key properties of the ceramic thermoelectrics SrTiO3?TiO2 are determined by the characteristics of a two-dimensional electron gas localized along the grain boundaries of SrTiO3 and TiO2 grains. In other words, a high Q-factor of similar thermoelectrics is possible only when we create a structure where the SrTiO3 and TiO2 grains are located in a "checkerboard" order throughout all the volume of the material. When this problem solved, it will be possible to manufacture complex YAG:RE3 + / SrTiO3?TiO2 composite structures in a single technological cycle," says Denis Kosyanov.

"The development of combined laser ceramics with thermoelectric layers is innovative task of a high interest. The results aim the development of a new field of knowledge - the physicochemistry of ceramic heterostructures. These works are conducted as a part of one of the main research activity of the FEFU key laboratory "Perspective Materials and Nanotechnologies". I want to point out that amidst the staff won RFBR's grant there is no a single Doctor of Science, and the average age of the performers is 27 years. When we formed the Laboratory at the beginning of 2018, we gave preference to talented young scientists, and now it gives a significant result," said the vice-rector for scientific work of the FEFU Kirill Golokhvast.

EurekAlert!, the online, global news service operated by AAAS, the science society: https://www.eurekalert.org/pub_releases/2018-09/fefu-fys091318.php