High verticality vapor-liquid-solid growth of GaAsBi nanowires using Ga-Bi assisted catalytic droplets.

GaAsBi nanowires (NWs) are promising for optoelectronic applications in the near- and mid-infrared wavelengths due to the optical properties of the Bi-containing compound and the nanowire structure benefits. In general, synthesizing the GaAsBi NWs results in uncontrollable metamorphic structures and spontaneous Bi-containing droplets. Here, we explore the potential of using the droplets as catalysts to form GaAsBi nanowires (hence, the vapor-liquid-solid growth mechanism) on GaAs (111) substrates by molecular beam epitaxy.

GaAs/GaAsPBi core-shell nanowires grown by molecular beam epitaxy.

We report on the growth, structural, and optical properties of GaAs/GaAsPBi core-shell nanowires (NWs) synthesized by molecular beam epitaxy (MBE). The structure presents advantageous optical properties, in particular, for near- and mid-infrared optical applications. Scanning electron microscopy shows that although the stems of GaAs/GaAsP and GaAs/GaAsBi core-shell NWs preserve the hexagonal prism shape, the GaAs/GaAsPBi core-shell NWs develop a quasi-three-fold orientational symmetry affected by the hexagonal prismatic core.

Nanoscale electrical analyses of axial-junction GaAsP nanowires for solar cell applications.

Axial p-n and p-i-n junctions in GaAsP nanowires are demonstrated and analyzed using electron beam induced current microscopy. Organized self-catalyzed nanowire arrays are grown by molecular beam epitaxy on nanopatterned Si substrates. The nanowires are doped using Be and Si impurities to obtain p- and n-type conductivity, respectively.

Correlated optical and structural analyses of individual GaAsP/GaP core-shell nanowires.

We report on the structural and optical properties of GaAsP/GaP core-shell nanowires (NWs) for future photovoltaic applications. The NWs are grown by self-catalyzed molecular beam epitaxy. Scanning transmission electron microscopy (STEM) analyses demonstrate that the GaAsP NW core develops an inverse-tapered shape with a formation of an unintentional GaAsP shell having a lower P content.

In situ passivation of GaAsP nanowires.

We report on the structural and optical properties of GaAsP nanowires (NWs) grown by molecular-beam epitaxy. By adjusting the alloy composition in the NWs, the transition energy was tuned to the optimal value required for tandem III-V/silicon solar cells. We discovered that an unintentional shell was also formed during the GaAsP NW growth.