Roles of biasing, disorder, defects, and geometry in the offset voltage of graphene Hall-effect sensors
Phys. Rev. Applied 25, 044076 – Published 27 April, 2026
DOI: https://doi.org/10.1103/6cw6-vpxg
Abstract
The dc offset voltage in Hall-effect magnetic sensors is a critical factor limiting the precision of low-strength magnetic field detection, yet its behavior in graphene Hall-effect sensors (GHSs) remains underexplored beyond simplistic models such as the lumped-element Wheatstone bridge. This study presents the first comprehensive investigation of offset voltage in GHSs by incorporating physics-based analytical models into a commercial finite-element-method solver through the magnetoconductivity tensor, and the analysis is further supported by the electrical characterization of fabricated local back-gated GHS (LBG-GHS) devices. Using this framework, we perform a systematic exploration of lithographic imperfections, biasing conditions, spatial channel disorders, and structural defects affecting the offset value. A comprehensive electrical evaluation is performed on 25 LBG-GHS devices for a statistical analysis, revealing variable offset voltage patterns that show soft odd-even symmetries and comparable device resistance trends with respect to the LBG variations. Through simulation and experimental correlation, we develop a physical interpretation of this observed soft odd-even symmetry in offset voltage, attributing it to spatial variations in charge carriers. Kelvin probe force microscopy measurement on a large-area () LBG-GHS device is taken to map local residual carrier variations. These measured and spatially low-pass-filtered carrier profiles are incorporated into the simulations to observe the transition from soft odd to soft even symmetry in offset voltage. Our findings demonstrate that current biasing is more effective in managing offset voltage in GHSs, providing critical insights into the optimization of graphene-based magnetic sensors for high-precision applications.
