Highly sensitive Al0.25Ga0.75As/In0.25Ga0.75As/GaAs quantum-well Hall devices with Si-delta-doped GaAs layer grown by LP-MOCVD

Abstract Quantum-well Hall devices based on Si-delta-doped Al0.25Ga0.75As/In0.25Ga0.75As/GaAs pseudomorphic heterostructure materials grown by the low-pressure metal organic chemical vapour deposition (LP-MOCVD) method have been successfully fabricated. A Si-delta-doped GaAs layer is introduced for the first time in the Hall device to reduce the thermal variation of electron concentrations and to improve its temperature characteristics. A high electron mobility of 8100 cm2V−1s−1 with a sheet carrier density of 1.5 × 1012cm−2 has been achieved at room temperature. A temperature coefficient of −0.015% K−1 with a product sensitivity of 420 V A−1T−1 has been obtained. High signal-to-noise (S/N) ratios corresponding to minimum detectable magnetic fields (Bmin) of 60 nT at 1 kHz and 110 nT at 100 Hz have been attained due to the reduced low-frequency noise from DX centres and the high mobility. These data belong to one of the best reported results.