Influence of Nanowire Density on the Shape and Optical Properties of Ternary InGaAs Nanowires

Abstract

We have synthesized ternary InGaAs nanowires on (111)B GaAs surfaces by metal-organic chemical vapor deposition. Au colloidal nanoparticles were employed to catalyze nanowire growth. We observed the strong influence of nanowire density on nanowire height, tapering, and base shape specific to the nanowires with high In composition. This dependency was attributed to the large difference of diffusion length on (111)B surfaces between In and Ga reaction species, with In being the more mobile species. Energy dispersive X-ray spectroscopy analysis together with high-resolution electron microscopy study of individual InGaAs nanowires shows large In/Ga compositional variation along the nanowire supporting the present diffusion model. Photoluminescence spectra exhibit a red shift with decreasing nanowire density due to the higher degree of In incorporation in more sparsely distributed InGaAs nanowires.

Au impact on GaAs epitaxial growth on GaAs (111)B substrates in molecular beam epitaxy

“…16 Among all kinds of metallic catalysts, Au has been commonly used to catalyze the growth of semiconductor nanowires 9,17 and nanowire heterostructures. [18][19][20] There are several approaches to prepare Au catalysts, such as aerosolgenerated Au particles, 21 colloidal Au particles, 22,23 electron beam lithography defined Au particles, 24 and Au particles generated by annealing of thin films. 25,26 Of these approaches, the thin film generated Au nanoparticles (TFA) is a simple and cost-effective approach, in which the Au nanoparticles are realized by decomposition of the Au thin films into nanoparticles during annealing process.…”

Structural characteristics of GaSb∕GaAs nanowire heterostructures grown by metal-organic chemical vapor deposition

“…Detailed substrate treatment can be found in Ref. 26. The substrates coated with Au particles were firstly annealed at 600°C under AsH 3 flow for 10 min to desorb surface contaminants and to alloy Au particles with Ga from substrates.…”

Imaging and optical properties of single core-shell GaAs-AlGaAs nanowires

“…The NWs have pronounced tapered shape with an average diameter of ~80 nm and average length of 6-8 µm. The tapering is due to the incorporation of reaction species from the (111) surface to the side wall [8]. We therefore estimate that the GaAs core is approximately 40 nm in diameter and the AlGaAs shell is 20 nm thick.…”