InSb Quantum-Well-Based Micro-Hall Devices: Potential for pT Detectivity

A series of high-mobility $\hbox{Al}_{0.12}\hbox{In}_{0.88}\hbox{Sb/InSb}$ heterostructures were grown by molecular beam epitaxy to investigate the fabrication of micro-Hall magnetic field sensors. By applying remote $\delta$-doping of different densities to control the 2-D electron density in the quantum channel, as well as scattering mechanisms, the detection limit of the micro-Hall device was improved. The present studies show that micro-Hall devices 35 $\mu\hbox{m}$ wide have the ability to detect a magnetic field of 25 nT at 300 K and 11 nT at 80 K operating at a frequency of 10 kHz. Our results indicate that the use of devices with larger sizes, based on the same material system, will lead to magnetic field detection in the pT range at low temperatures and sub-nT range even at room temperature.