High-Temperature Thermal Stability of a Graphene Hall Effect Sensor on Defect-Engineered 4H-SiC(0001)

In this letter, we demonstrate a Hall effect sensor in the technology of amorphous-Al₂O₃-passivated transfer-free p-type hydrogen-intercalated quasi-free-standing epitaxial Chemical Vapor Deposition graphene on semi-insulating high-purity on-axis 4H-SiC(0001), pre-epitaxially modified with 5-keV hydrogen (H⁺) ions. The sensor operates between 305 K and 770 K, with a current-mode sensitivity of ~75 V/AT and thermal stability below 0.15 %/K ( $\leqslant ~0.03$ %/K in a narrower range between 305 K and 700 K). It is a promising two-dimensional platform for high-temperature magnetic diagnostics and plasma control systems for modern tokamak fusion reactors.