Magnetic field sensitivity of In0.75Ga0.25As Hall nanoprobes

We have fabricated and characterized Hall probes on an In0.75Al0.25As/In0.75Ga0.25As two-dimensional electron gas with lateral sizes down to 100 nm. We studied the dependence of the low temperature (4 K) magnetic field sensitivity on the probe size, showing that the best flux sensitivity is achieved by devices of ≈200≈200 nm, employing highly doped systems (n∼1012n∼1012 cm−2). Hall bars with sizes down to the range of 200–250 nm show a magnetic field sensitivity of a few Gauss, corresponding to a flux sensitivity equal to ≈10−2Φ0≈10−2Φ0.