Electrical charge transport of n–InAs epitaxial films on GaAs

Molecular beam epitaxy has been used to grow epitaxial InAs onto (0 0 1) oriented SI–GaAs, at different substrate temperatures Ts=(440–506 °C) and different V/III flux ratios. No influence of growth rate on the microstructure of the layers has been detected. Transport properties of the layers have been investigated by Hall effect measurements under a magnetic field of 0.6 T, at temperatures from 3.5 to 300 K. InAs samples exhibited a characteristic maximum of Hall coefficient (minimum of Hall concentration) at temperatures of about 60 K, which is not typical for semiconductors. We propose a model for interpreting this behaviour, which is extended to other nominally undoped samples.