“The research may help to prepare semiconductor compounds surfaces in the semiconductor industry. It could also be key to developing a killer application for the future graphene industry.”Pascal Pochet
Researchers have provided an atomic description for a particular surface reconstruction that helps advance graphene science, in a study that also demonstrates the existence of a new kind of reconstruction mixing order and disorder at the surface of a semiconductor compound, highlighting the need for much more complex reconstruction for these type of surfaces.
In a letter to the journal Applied Physics Letters [Machado-Charry et al. Appl. Phys. Lett (2020) DOI: 10.1063/1.5143010], a team from Université Grenoble Alpes, Graz University of Technology, Universidad Autonoma de Madrid, Université Paris-Saclay and Université de Montréal show how to better control the graphene on SiC substrate, which is a helpful platform for growing other 2D materials that benefits from remote epitaxy.
The work builds on advances in the fields of 2D materials and semiconductor compounds over the last decade since high-quality graphene was mostly developed achieved through silicon sublimation from silicon carbide (SiC) wafers. Although there has been much interest in the 3x3 reconstruction of the C-face of SiC, its atomic arrangement reconstruction has remained unknown, despite the increased attention on grapheme research. SiC wafers are seen as a key semiconductor material that can offer unique electrical properties and excellent thermal properties, and are more suitable for high temperature and high power device application than silicon or gallium arsenide (GaAs) wafers.
The underlying model of the 3x3 reconstruction occurring at its surface has been unknown since first reported in 1997. From intensive density functional theory, they discovered that this reconstruction comes from an ordered all-silicon over-layer adopting a honeycomb-kagome lattice. The model was characterized by scanning tunnelling microscopy simulation, allowing for the model to be refined, which demonstrated that a disorder substitution is at play below the over-layer.
The combination of the two reconstruction levels makes this surface reconstruction unique among semiconductors. In addition to its significance of SiC for graphene growth or powerful electronics, the reconstruction could prove useful in applied physics, with an understanding of the physics of surface reconstruction being crucial in many areas – not just in growth science, but also for tuning new devices for interfacial physics such as 2D electron gas or surface superconductivity.
The team now hopes to develop materials exhibiting surface superconductivity and semiconductor compounds based materials for quantum computing, as well as to investigate more systematic approaches to characterizing the reconstruction of these surfaces. As group leader Pascal Pochet told Materials Today, “The research may help to prepare semiconductor compounds surfaces in the semiconductor industry. It could also be key to developing a killer application for the future graphene industry.”
Atomic arrangement reconstruction of the C-face of SiC