The transport properties of InAs nanowires: an introduction to MnAs/InAs heterojunction nanowires for spintronics

Abstract

Semiconducting nanowires are of high interest as building blocks for nanoscaled electronic or optoelectronic devices, such as field-effect transistors, gas sensors or light-emitting diodes. Due to their unique structural properties with a high surface to volume ratio and quasi-one dimensionality, they exhibit interesting new optical and electronic properties. As the device performance strongly depends on charge carrier density, carrier lifetime, and carrier mobility, a detailed knowledge of the transport properties in quasi-one dimensional nanostructures is essential. Especially, InAs nanowires are of considerable interest for high performance transistors, thermoelectrics, spintronics or quantum computing devices as they not only exhibit high carrier mobility but also a strong spin-orbit coupling and a large g-factor. Furthermore, at low temperatures a surface accumulation layer can occur in InAs nanowires after surface treatments resulting in interesting mesoscopic transport phenomena such as universal conductance fluctuations or weak antilocalisation. However, for nanoscaled magnetoelectronic or spintronic applications nanowires with adjustable ferromagnetic properties are desirable. As the growth of diluted magnetic semiconductors and semiconducting nanowires with a Curie-temperature above 300 K is still challenging, MnAs/InAs heterojunction nanowires, where ferromagnetic nanoclusters are embedded in a semiconducting matrix, may represent a promising alternative. Additionally, such heterojunction nanowires have been reported to exhibit huge magnetoresistance effects as well as a relatively long spin-relaxation time.