Mg-Doped GaAs Nanowires with Enhanced Surface Alloying for Use as Ohmic Contacts in Nanoelectronic Devices

In this work, we have investigated the structural and electronic properties of Mg-doped GaAs(111) nanowires synthesized through a vapor-liquid-solid growth mechanism. The crystalline structure of these nanowires was measured using synchrotron X-ray diffraction, while their electronic structure was addressed by scanning tunneling spectroscopy. Scanning tunneling microscopy measurements revealed that conducting Ga2Mg/Mg clusters are observed at {110} nanowire lateral surfaces, allowing electrical contacts with reduced Schottky barriers. This suggests that similar alloyed surfaces can be produced with other dopants, enabling the development of distinct Ohmic contacts in these systems. Density functional theory was used to investigate the electronic response of Ga2Mg. While at room temperature, electronic variable-range hopping drives the nanowires into a metallic behavior, quantum confinement is observed at low temperatures.