Fabrication and Characterization of Template-Defined Scalable InAs Nanowire Networks

Semiconductor nanowires with strong Rashba-type spin-orbit interaction are a great platform to create and study novel quasiparticles, such as Majorana- and para-fermions. These excitations with non-Abelian statistics are of fundamental interest offering promising applications in topological quantum computing. Here, we report recent results on templated InAs nanowire networks grown on GaAs nanomembranes^[1]. A fabrication process for contacting, encapsulation in an ALD dielectric, and electrostatic gating of wires grown on [111] and [100] GaAs substrates has been developed and implemented. The low-temperature conductance behavior of the devices has been analyzed as a function of applied magnetic field and gate voltage. The investigation aims at fundamental system properties like mean free path, coherence length, and spin-orbit length. Further, transport behavior over junctions between the nanowires - enabled by the crystal-lattice symmetries - has been explored. The work lays the foundation for the integration of superconductors in the devices, which provides a means for studying the behavior of hybrid structures with strong spin-orbit interaction.

[1] M. Friedl et al., Nano Lett. 18, 2666-2671 (2018)