Knowledge graphs (KGs) play an important role in the structured representation and linking of data, information, and knowledge. As a result, knowledge graphs are finding broad application in the field of research data management. Building on the established plasma metadata schema Plasma-MDS and the plasma ontology Plasma-O, the development of Plasma-KG (https://vivo.plasma-mds.org) was initiated to represent reusable entities with persistent identifiers in the field of low-temperature plasma physics. This contribution introduces the essential concepts of Plasma-KG and shows how various data sources can be connected via these formally described entities. The addressed fields of application include content enrichment from knowledge graphs for patents, scientific articles, and mathematical models. It is demonstrated how the future physics information service "FID Physik" can benefit from Plasma-KG as a semantic data platform.