Au wetting and nanoparticle stability on GaAs(111)B

Abstract

Au nanoparticles and Au films for growth of nanowires on the GaAs͑111͒B surface have been studied by a combination of experimental and theoretical techniques. If Au is present in either form, annealing to temperatures relevant for nanowire growth results in the formation of a thin Au wetting layer. Based on density functional theory calculations and experimental data, a structural model is proposed with an Au atom on every third threefold hollow hcp site of the Ga lattice. The authors observe that the stability of Au nanoparticles is governed by the presence of the wetting layer and outdiffusion of Au from the nanoparticles.

Gold-induced surface reconstruction on GaAs(111)Bsurface

“…The electronic structure of this minimum-energy structure is also determined and shown to be metallic. The simulated STM images support the Au-induced surface reconstruction model proposed by Hilner et al [10].…”

“…0.18 eV, which is very small as compared with other GaAs(001) surfaces. This result indicates the formation of a Au wetting layer which was proposed by Hilner et al [10]. A deep understanding of the electronic structure can be obtained by an accurate theoretical study of the STM images.…”

“…Au is the most widely studied metal element in semiconductor technology [8,9]. Recently, Hilner et al [10], using low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) images, concluded that a Au-covered GaAs(111)B surface predominantly exhibits a ð ffiffi ffi 3 p £ ffiffi ffi 3 p Þ reconstruction at low coverage of Au atoms. This model is formed by one Au adatom per unit cell located in a threefold hollow (H 3 ) site, but does not satisfy the electron counting rule (ECR) [11].…”

Surface structure and morphology of InAs(111)B with/without gold nanoparticles annealed under arsenic or atomic hydrogen flux

“…The most As poor reconstruction on GaAs(1 1 1)B, called the (1 Â 1) HT reconstruction has not been studied in very much detail. We have previously observed it after annealing at 600°C in UHV [7] and attributed it to Ga-trimers. The proposal of the (2 Â 2) structure on InAs(1 1 1)B consisting of As ad trimers is supported by the STM images in which the structural units looks triangular (seen in the inset in Fig.…”

“…It certainly motivates further investigations of the substrate structure down to the atomic scale since it determines for example the values of diffusion coefficients needed in the theoretical modeling. It is known that also the Au nanoparticles, acting as seeds for growth, may have an effect on the substrate structure [6,7]. On the Si(1 1 1) and GaAs(1 1 1)B surfaces Au diffuses from the particles onto the surface creating a thin wetting layer and changing the surface properties at temperatures relevant for nanowire growth.…”