Characterization of the Interface of Gold and Silver Nanostructures on InP and GaAs Synthesized via Galvanic Displacement

Abstract

This work describes an investigation of the nature of the interface formed between the metals gold and silver, and the technologically relevant semiconductor substrates, InP and GaAs, produced via room temperature galvanic displacement. Immersion of these III-V semiconducting materials in a solution of the ionic gold and silver precursors results in deposition of firmly bound metal on the surface with varying morphologies, depending upon the conditions. Depth profile XPS indicates the presence of sandwiched intermetallic layers in the case of gold on GaAs and InP, but little evidence of a corresponding intermetallic with silver was observed. Cross section scanning Auger electron line profile spectra suggest little diffusion of the metals into the semiconductor lattice. It appears, therefore, that in the case of gold on InP and GaAs, dissociative diffusion of the semiconductor into the metal is favored, leading to a structure in which the intermetallic is located at an abrupt semiconductor-intermetallic boundary. The compositions of the gold intermetallics for GaAs and InP are most likely γ-Au 9 Ga 4 and AuGa for the first and AuIn and AuIn 2 for the second, respectively.

Precise control of configuration, size and density of self-assembled Au nanostructures on 4H-SiC (0001) by systematic variation of deposition amount, annealing temperature and duration

“…As another aspect, the Au NPs on 4H-SiC (0001) for a given deposition amount showed a relatively much smaller size distribution (i.e. at 3 nm, the AH is ∼8.7 nm and the LD is ∼45.6) with a highly packed density as compared with the counterparts on GaAs [33][34][35] and Si, 29,36 which can likely be due to the much higher diffusion barrier caused by the higher surface roughness of SiC. 37 Fig.…”

High performance III-V photoelectrodes for solar water splitting via synergistically tailored structure and stoichiometry

“…The process begins with the oxide-removal of as-grown p-type GaInP 2 in dilute NH 4 OH and chromium etchant, followed by dipping into an aqueous solution of silver nitrate (AgNO 3 ) and hydrofluoric acid (HF). The silver cations in the solution are electrolessly reduced to form silver nanoparticles that can serve as a hard mask in successive dry etching of GaInP 2 , where the size and density of silver nanoparticles can be readily controlled by adjusting the concentration of precursors and/or plating time 25,26 . Subsequently, inductively coupled plasma reactive ion etching (ICP RIE) was performed using a gas mixture of BCl 3 /N 2 to form cone-shaped nanopillars of GaInP 2 , followed by the removal of residual silver by a wet chemical etchant.…”

Organic-Free Au-Pd Alloys on Germanium Substrate via Spontaneous Galvanic Displacement Reaction

“…To take the best advantage of its simplicity, the galvanic displacement process has been mostly applied to synthesize monometallic noble metal nanocrystals such as Au, Ag, Pd, Pt, and etc. [8][9][10][11][12][13] on Ge or other semiconductors such as GaAs, InP substrate, of which cations generally have significantly large positive standard reduction potential values. On the contrary, there is not much report about the formation of composite alloys which are of great interest from scientific and technological perspectives owing to their composition-dependent optical, catalytic, electronic, and magnetic properties.…”

“…[8][9][10][11][12][13] The galvanic displacement, a mechanism-based nomenclature for the spontaneous metal nanocrystal formation, involves direct electron transfer from metal or semiconductor substrates (electron donors) to metallic precursor cations (electron acceptors) at room temperature according to their relative electrochemical redox potentials. A representative example of metal nanocrystals synthesized by the galvanic displacement is Au nanoparticles on germanium (Ge) surface.…”