| Title: | Wpływ wysokiego ciśnienia gazu N2 na mechanizmy krystalizacji i właściwości fizyczne h-BN |
| Project leader: | Bohdan Sadovyi |
| Laboratory: | Semiconductor Physics Laboratory (NL-2) |
| Call/Programme name: | Long-term program of support for Ukrainian research teams |
| Project number: | PAN.BFB.S.BWZ.369.022.2023 |
| Implementation date: | 01.09.2023 31.08.2025 |
| Implementing entity: | Institute of High Pressure Physics |
| Total funding granted: | 1 584 802 zł |
| Funding for the entity: | 1 584 802 zł |
| Funding institution: | Narodowa Akademia Nauk Stanów Zjednoczonych (NAS) |
Project description
| The project aims to develop a new approach to growing structurally perfect single crystals of hexagonal boron nitride (h-BN) of large size and high purity by temperature gradient method from a solution of boron and nitrogen in a solvent based on magnesium with gallium under the high pressure of nitrogen gas. The research will make it possible to grow h-BN single crystals suitable for a wide range of applications in 2D material-based electronic and optoelectronic devices and nanophotonics, which would benefit from the wide bandgap, low dielectric constant, mechanical robustness, oxidation resistance, high thermal conductivity and atomically flat surface of h-BN. To realize the potential of h-BN for device applications, materials synthesis and processing techniques must be advanced, including bulk crystal growth. The chemical purity of single crystalline h-BN is a crucial issue. Large area h-BN single crystals with low defect density and contamination are needed to achieve the best device performance. The proposed approach uses high-pressure systems with a gaseous pressure medium to crystallize h-BN from a solution of boron and nitrogen in solvents based on liquid metals or alloys. High pressure gas equipment has already been successfully used to obtain the first structurally perfect GaN single crystals worldwide by solution crystallization. Thus, the project will investigate the processes of h-BN crystallization in a temperature gradient under N2 gas pressure from a solution of boron and nitrogen in solvents selected from among those already used in the world – Mg and Ni-Cr, Ni-Mo, and Fe-Cr, that will be modified by adding gallium. The influence of growth conditions, especially nitrogen gas pressure, on the crystallization processes of h-BN single crystals and their structural, morphological, and optical properties will be studied. The obtained results as feedback will be used to improve the synthesis conditions, which will allow for increasing the size of h-BN single crystals maintaining high crystal quality and purity. Mechanical or chemical exfoliation will be performed to obtain large-area h-BN monolayers on substrates, and their structure and physical properties will be investigated. The performance of the exfoliated h-BN mono- and multilayers will be probed for surface-enhanced Raman spectroscopy (SERS) experiments both as enhancing media and as oxidation protective coating for noble metal-based SERS substrates. Furthermore, the exfoliated layers of h-BN will also be provided to investigate their performance for heatsinking in power electronic applications and enhancing the emission of n-ZnO/p-hBN/p-GaN LED heterojunctions. The 2D spatial maps of heat loss efficiency will be studied by the optical µ-Raman spectroscopy method with submicron spatial resolution. Recently, in the IHPP PAS, the first positive results on the synthesis of single crystals of h-BN under high N2 gas conditions have already been obtained, confirming the actual feasibility and perspective of the proposed research on the synthesis of h-BN single crystals with high structural quality and lateral dimensions sufficient for mechanical manipulation. The progress achieved during the implementation of the project will determine new opportunities for future research on h-BN applications in Ukraine. |