Highly sensitive micro-Hall devices based on Al0.12In0.88Sb∕InSb heterostructures

Abstract

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 1800VA−1T−1 at 77K and 1220VA−1T−1 at 300K 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 20Hzto20kHz. The low detection limit of 28nT at 300K and 18nT at 77K were found at high frequencies where the Johnson noise is dominant. A measured detection limit per unit device width of 630pTmmHz−1∕2 is reported indicating the potential for picotesla detectivity.