The electrodeposition of metal onto a low energy electrode surface like graphite or H-terminated silicon produces mesoscopic metal particles that are broadly distributed in diameter Broad size distributions are observed even in cases where the nucleation of metal is temporally controlled For this reason, electrodeposition has been infrequently used as a means for obtaining metal nanostuctures The central problem is the diffusional “cross-talk” that exists between neighboring metal nanostructures on the electrode surface Evidence for this diffusional interparticle coupling is encoded into particle size and position distributions obtained from experimental data and from Brownian Dynamics computer simulations of nanostructure growth Diffusional cross-talk between nanostructures can be turned off using either of two growth strategies described in this paper These methods permit the size-selective electrodeposition of metal nanoparticles and nanowires that are narrowly distributed in diameter

Mesoscopic Metal Particles and Wires by Electrodeposition

Bioresorbable silicon electronics technology offers unprecedented opportunities to deploy advanced implantable monitoring systems that eliminate risks, cost and discomfort associated with surgical extraction. Applications include postoperative monitoring and transient physiologic recording after percutaneous or minimally invasive placement of vascular, cardiac, orthopaedic, neural or other devices. We present an embodiment of these materials in both passive and actively addressed arrays of bioresorbable silicon electrodes with multiplexing capabilities, which record in vivo electrophysiological signals from the cortical surface and the subgaleal space. The devices detect normal physiologic and epileptiform activity, both in acute and chronic recordings. Comparative studies show sensor performance comparable to standard clinical systems and reduced tissue reactivity relative to conventional clinical electrocorticography (ECoG) electrodes. This technology offers general applicability in neural interfaces, with additional potential utility in treatment of disorders where transient monitoring and modulation of physiologic function, implant integrity and tissue recovery or regeneration are required.

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Bioresorbable silicon electronics for transient spatiotemporal mapping of electrical activity from the cerebral cortex

Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. These porous nanowires also retain the crystallographic orientation of the wafer from which they are etched. Electron microscopy and diffraction confirm their single-crystallinity and reveal the silicon surrounding the pores is as thin as several nanometers. Confocal fluorescence microscopy showed that the photoluminescence (PL) of these arrays emanate from the nanowires themselves, and their PL spectrum suggests that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices.

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Single crystalline mesoporous silicon nanowires.

High-Performance Macroporous Bulk Silicon Anodes Synthesized by Template-Free Chemical Etching

Thin noble metal films have been prepared as a result of the immersion of germanium substrates into dilute, aqueous solutions of AuCl4-, PdCl42-, or PtCl42-, respectively. Deposition proceeds via galvanic displacement in the absence of fluoride, pH adjusters, complexing agents, or external reducing agents. This manner of metal deposition serves as a cost-effective, high-throughput methodology with control over surface morphology and deposition rate by modulation of plating parameters such as concentration, temperature, and immersion time.

/pdf/controlled-electroless-deposition-of-noble-metal-2x0cnohm84.pdf

Controlled Electroless Deposition of Noble Metal Nanoparticle Films on Germanium Surfaces

The general concepts governing the electrochemical deposition of metal films onto semiconductors are discussed Deposition onto semiconductor surfaces is complicated due to the band structure of the semiconductor, which affects both the thermodynamics and the kinetics of metal deposition processes The influence of the potential distribution at the semiconductor/solution interface on the charge transfer mechanisms involved in deposition of metals is discussed Models for electrochemical nucleation and growth are described and the influence of the unique physical properties of semiconductors is analysed Finally, we present recent results for electrochemical deposition of gold, copper and platinum onto n-type silicon

https://iopscience.iop.org/article/10.1088/0022-3727/31/16/001/pdf

J. G. Long

Papers

Electrochemical deposition of metals onto silicon