ABSTRACT
In this work the structure of ternary Ga x In1 - x P nanowires is investigated with respect to the chemical composition and homogeneity. The nanowires were grown by metal-organic vapor-phase epitaxy. For the investigation of ensemble fluctuations on several lateral length scales, X-ray diffraction reciprocal space maps have been analyzed. The data reveal a complicated varying materials composition across the sample and in the nanowires on the order of 20%. The use of modern synchrotron sources, where beam-sizes in the order of several 10 µm are available, enables us to investigate compositional gradients along the sample by recording diffraction patterns at different positions. In addition, compositional variations were found also within single nanowires in X-ray energy dispersive spectroscopy measurements.
ABSTRACT
Non-tapered vertically straight Ga(x)In(1-x)P nanowires were grown in a compositional range from Ga(0.2)In(0.8)P to pure GaP in particle-assisted mode by controlling the trimethylindium, trimethylgallium and hydrogen chloride flows in metal-organic vapor phase epitaxy. X-ray energy dispersive spectroscopy in transmission electron microscopy revealed homogeneous radial material composition in single nanowires, whereas variations in the material composition were found along the nanowires. High-resolution x-ray diffraction indicates a variation of the material composition on the order of about 19% measuring an entire sample area, i.e., including edge effects during growth. The non-capped nanowires emit room temperature photoluminescence strongly in the energy range of 1.43-2.16 eV, correlated with the bandgap expected from the material composition.
