Growth and electrical characterization of modulation doped core-shell GaAs/AlGaAs nanowires

In this work we will present the electrical properties of self-catalyzed, modulation (remotely) doped GaAs/AlGaAs core-shell nanowires grown by molecular beam epitaxy. The remote doping with Si delta-layer in the AlGaAs shell, which is deposited on the {110} side facets of the GaAs core, results in the formation of complex one (1d) and two (2d) dimensional electron channels at the interface between the GaAs and the AlGaAs, as shown by nextnano3 simulation of the electron density. The n-type behavior of the doping was confirmed with back gate dependent measurements on the fabricated field effect transistor devices and the occurrence of the persistent photoconductivity effect at low temperatures. Magnetic field studies at low temperatures revealed a complex oscillatory behavior of the magnetoresistance, which is due to the superposition of the 2d and 1d channels of electrons on the side facets and the edges, respectively. Furthermore, we discuss the dependence of the electrical properties on the crystal structure of the GaAs core, and the feasibility of obtaining high electron mobilities in these systems.