Alloy formation during molecular beam epitaxy growth of Si-doped InAs nanowires on GaAs[111]B

Abstract

Vertically aligned InAs nanowires (NWs) doped with Si were grown self-assisted by molecular beam epitaxy on GaAs[111]B substrates covered with a thin SiO x layer. Using out-of-plane X-ray diffraction, the influence of Si supply on the growth process and nanostructure formation was studied. It was found that the number of parasitic crystallites grown between the NWs increases with increasing Si flux. In addition, the formation of a Ga 0.2 In 0.8 As alloy was observed if the growth was performed on samples covered by a defective oxide layer. This alloy formation is observed within the crystallites and not within the nanowires. The Ga concentration is determined from the lattice mismatch of the crystallites relative to the InAs nanowires. No alloy formation is found for samples with faultless oxide layers.

Effect of the Composition on the Nonlinear Optical Response of AuxAg1–x Nano-Alloys

“…In order to take advantage of the properties of alloyed NPs, the key factor is their preparation, which should facilitate the effective control of their composition. During the last few years, several methods have been developed for the synthesis of alloyed NPs, as for example pulsed electrodeposition, 13 chemical reduction method, 14 evaporation of metallic bulk solid solutions, 15 sol−gel, 16 molecular beam epitaxy, 17 biogenic synthesis, 18 microreaction, 19 digestive ripening, 20 and different laser ablation based approaches. 21 Among the various preparation techniques, laser ablation in liquids has been demonstrated as the most efficient and flexible and prevailed almost all other preparation techniques of NPs.…”

“…The optical properties of the Au x Ag 1 – x nanoalloys are determined to a large extent by the presence of a single plasmon band, lying between the positions of the plasmon bands of pure gold and pure silver, at about 400 and 530 nm, respectively. Its spectral position and intensity depends closely on the alloys’ composition. ,− In fact, it is the presence of a single plasmon band that indicates the successful synthesis of the alloy and excludes the formation of core–shell like structure . Some efforts to explain and describe the plasmonic feature of nanoalloys have been based on the effective medium approximation, a method widely used for describing the optical properties of composite materials .…”

Structural and electrical properties of catalyst-free Si-doped InAs nanowires formed on Si(111)

“…In the previous report on transport properties of InAs NW with high stacking fault, the carrier mobility was increased with increasing Si-doping level 15 . Although the reduction in the resistivity of InAs NWs by the introduction of Si has been recently reported, the structural dimensions of InAs NWs were considerably changed 15 16 17 18 19 . However, a relatively low resistivity of Si-doped InAs NWs in this work was achieved without significant change in structural dimensions.…”

“…In the Volmer-Weber growth mode, interactions between adatoms are stronger than those between the adatom and surface, leading to the formation of InAs clusters or islands on Si substrates. Many research groups reported doping effects on the electrical, structural and optical properties of InAs NWs for the application of optoelectronic devices 13 14 15 16 17 18 19 20 . Most of the previous reports on doping for InAs NWs showed a significant change in size and shape 15 16 17 18 19 .…”

Nanowire Electronics: From Nanoscale to Macroscale

“…Scanning probe methods, such as scanning tunneling microscopy, , Kelvin probe force microscopy, , and scanning photocurrent microscopy, − can be used for quantitatively determining the doping profile at the surface of nanowires with a high spatial resolution. Some other technologies, including electron energy loss spectroscopy, X-ray energy-dispersive spectroscopy, , and out-of-plane X-ray diffraction, , may also be explored for identifying and/or mapping the dopants in nanowires.…”