Photoelectrochemically‐Induced Gold Deposition on p ‐ GaAs Electrodes: Part I . Nucleation and Growth

Abstract

This paper reports on the deposition of Au on cathodically biased p-GaAs electrodes from alkaline KAu(CN)2 solutions in the dark or under illumination. Nucleation and growth of Au have been studied by potentiodynamic and potentiostatic current measurements in combination with scanning and transmission electron microscopy. Au deposition is characterized by progressive nucleation and three-dimensional growth followed by coalescence of Au particles. Different mechanisms of electron transfer processes occurring during nucleation and growth are discussed. Au nucleation in the dark occurs readily at relatively high-doped (>5 • 10LT/cm 3) electrodes, both in the absence and presence of excess CNions. Selective photoinduced nucleation is possible on low-doped (<2 • 10~V/cm3) electrodes in a solution with excess CNions. It is observed that the critical size of Au nuclei is smaller than 1 nm. Growth of previously formed Au nuclei can proceed in the dark and is initially controlled both by kinetic factors and diffusion of Au(CN)2 ions. Our results indicate that only a small potential barrier exists between p-GaAs and deposited Au particles. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.117.10.200 Downloaded on 2015-06-22 to IP

Influence of the crystal orientation on the electrochemical behaviour of n-GaAs in Au(i)-containing solutions

“…As our specimens are lowdoped, we assume that electrodeposition of Au occurs only when the negative potential V D is applied. 16 This allows the calculation of the charge, needed to deposit layers of a certain average thickness, by means of the Faraday equation, assuming that all the charge is used for the reduction of the gold(I)-ions. Layers with thicknesses varying between 15 nm and 300 nm were deposited on both crystal faces with the deposition potential V D ranging within the same potential window as in the chronoamperometry measurements.…”

Electrodeposition of gold from cyanide solutions on different n-GaAs crystal faces

“…V D ranged within the potential window where deposition transients were observed, without the interference of H 2 (g)-evolution. From earlier work [2,3,7], it was concluded that electrodeposition of Au on n-GaAs is, under the conditions (N D and electrolyte solution) of this work, a conduction band process. So, deposition occurs only when the negative potential V D is applied.…”

Facile and Electrically Reliable Electroplated Gold Contacts to p-Type InAsSb Bulk-Like Epilayers

“…In the first one, an approximately 600 nm thick Au contact layer was obtained using potassium dicyanoaurate, K[Au(CN) 2 ], and a water solution as an electrolyte under 350–375 µA/cm 2 current density. K[Au(CN) 2 ] solution was utilized for the deposition of Au on p - and n -type GaAs nearly three decades ago [ 41 , 42 , 43 ]. The same protocol was used in our previous work on binary arsenide, namely InAs [ 34 ], proving that these contacts adhere well to arsenide epilayers.…”

“…The same protocol was used in our previous work on binary arsenide, namely InAs [34], proving that these contacts adhere well to arsenide epilayers. Regarding Au electrodeposition on A III -As, there have been only a few reports, not necessarily on InAsSb but rather on GaAs [41][42][43]. A study on the electrochemical behavior of distinct GaAs surfaces in an Au-containing aqueous electrolyte solution revealed that the nucleation mechanism of Au on these surfaces depends on the chemical composition of the surface [22,44].…”