Highly sensitive micro-Hall devices based on Al0.12In0.88Sb/InSb heterostructures -: art. no. 014506

Micro-Hall devices based on modulation-doped Al0.12In0.88Sb/InSb heterostructures are fabricated and studied in terms of sensitivity and noise. Extremely high supply-current-related magnetic sensitivities of 1800 V A(-1) T-1 at 77 K and 1220 V A(-1) T-1 at 300 K are reported and observed to be independent of the bias current. The detection limit of the devices studied at low and room temperature are at nanotesla values throughout the broad frequency range from 20 Hz to 20 kHz. The low detection limit of 28 nT at 300 K and 18 nT at 77 K were. found at high frequencies where the Johnson noise is dominant. A measured detection limit per unit device width of 630 pT mm Hz(-1/2) is reported indicating the potential for picotesla detectivity. (c) 2005 American Institute of Physics.