Sensitivity of Novel Micro-AlN/GaN/AlN Quantum Well Hall Sensors

We have grown AlN/gallium nitride (GaN)/AlN heterostructures by molecular beam epitaxy (MBE) and fabricated Hall sensors. In a comparison with fabricated AlGaN/AlN/GaN Hall sensors, we find that the AlN/GaN/AlN quantum well (QW) Hall sensors have higher sensitivity under constant current bias. In addition, the application of a gate voltage shows a further increase in the Hall sensitivity from 3.6 to 6.1 VW
$^{-{1}}\text {T}^{{-{1}}}$
, without a significant change in the operating parameters. This is because the gate voltage restricted the current flow resulting in an increase carrier velocity and electric field at precisely the Hall measurement site while keeping the device applied power approximately the same.