Characterisation of InGaAs/InP microscopic Hall probe arrays with a 2DEG active layer

Highly-sensitive cryogenic microscopic Hall probe arrays based on an epitaxial InGaAs/InP heterostructure with a two-dimensional electron gas (2DEG) were prepared and characterised in high magnetic fields at 0.3 K. A model of the heterostructure including a self-consistent description of coupled Poisson and Schrödinger equations was solved to optimise its design. Test arrays exhibit a constant 2DEG concentration at 4.2–100 K, which gives a temperature coefficient lower than 100 ppm °C−1. The magnetic sensitivity is ≥1250 VA−1T−1. Quantum oscillations in the 2DEG structure in high magnetic fields at temperatures below 4.2 K can be suppressed by increasing bias current supplied to the arrays respecting their dimensions. Noise characteristics at 300 K are also presented.