Growth and optical properties of In x Ga1-x P nanowires synthesized by selective-area epitaxy

Ternary III-V nanowires (NWs) cover a wide range of wavelengths in the solar spectrum and would greatly benefit from being synthesized as position-controlled arrays for improved vertical yield, reproducibility, and tunable optical absorption. Here, we report on successful selective-area epitaxy of metal-particle-free vertical In (x) Ga1-x P NW arrays using metal-organic vapor phase epitaxy and detail their optical properties. A systematic growth study establishes the range of suitable growth parameters to obtain uniform NW growth over a large array. The optical properties of the NWs were characterized by room-temperature cathodoluminescence spectroscopy. Tunability of the emission wavelength from 870 nm to approximately 800 nm was achieved. Transmission electron microscopy and energy dispersive X-ray measurements performed on cross-section samples revealed a pure wurtzite crystal structure with very few stacking faults and a slight composition gradient along the NW growth axis.