Researchers at the German RWTH University and AMO GmbH Aachen fabricated highly sensitive Hall Effect sensors using single layer graphene. Graphene's very high carrier mobility at room temperature and very low carrier densities make it a material that can outperform all currently existing Hall sensor technologies.
The researchers protected the graphene from ambient contamination by encapsulating it with hexagonal boron nitride layers. The consequently fabricated devices showed a voltage and current normalized sensitivity of up to 3 V/VT and 5700 V/AT, respectively. These values are more than one order of magnitude above the values achieved in Silicon-based devices and a factor of two above the values achieved with the best III/V semiconductors Hall sensors in ambient conditions. In addition, these results are far better than the earlier reported graphene Hall sensors on Silicon oxide and Silicon carbide substrates.
This new sensitivity level may enable devices with higher precision, lower energy consumption with smaller dimensions. This work may even open the door for using graphene in more commercial applications, as Hall sensors are integral part of many household appliances like position sensors, DC current transformers, automotive indicators and more.