Optical properties and thermal conductivity of resistive Au nanogranular films
type: CreativeWork
description: Networks based on nanometer-sized resistively switching junctions are considered promising elements for the fabrication of neuromorphic computing architectures. Such architectures are intended for data-intensive processing tasks in a way similar to synapse networks. Resistive switching refers to the reversible change of resistance of a dielectric material in response to the application of a strong external electric field. Networks of gold clusters, fabricated by supersonic cluster beam deposition, are ohmic conductors when deposited but can be electrically activated to a state where their conduction behaviour is no longer linear, and where they can be reproducibly switched between low resistance and high resistance states. At room temperature and atmospheric pressure, stability and reproducibility of the resistance switching of such nanogranular Au films was observed to last over many hours thus making them ideal test beds for exploration of the basic mechanisms of the switching processes and allow convenient fabrication of devices that may have neuromorphic properties. The objective of this PhD project was to study other properties of these same nanogranular gold films, namely their linear and nonlinear optical properties and their thermal conductivity. The linear optical properties were observed using femtosecond transient absorption spectroscopy (fTAS) and their film morphology was explored with atomic force microscopy. The switch activation mechanisms that transformed the nanogranular Au film into a resistively switchable one, clearly influenced the plasmonic effects. This implies that the plasmonic effects of the nanogranular Au film can be tuned using resistive switching and since strong plasmonic effects enhance light absorption, such films may be used for optical switching applications and modulation of optical signals in artificial optoelectronic synapses that have been engineered plasmonically. As a result of switch activation and resistive switching, stru…
abstract: Networks based on nanometer-sized resistively switching junctions are considered promising elements for the fabrication of neuromorphic computing architectures. Such architectures are intended for data-intensive processing tasks in a way similar to synapse networks. Resistive switching refers to the reversible change of resistance of a dielectric material in response to the application of a strong external electric field. Networks of gold clusters, fabricated by supersonic cluster beam deposition, are ohmic conductors when deposited but can be electrically activated to a state where their conduction behaviour is no longer linear, and where they can be reproducibly switched between low resistance and high resistance states. At room temperature and atmospheric pressure, stability and reproducibility of the resistance switching of such nanogranular Au films was observed to last over many hours thus making them ideal test beds for exploration of the basic mechanisms of the switching processes and allow convenient fabrication of devices that may have neuromorphic properties. The objective of this PhD project was to study other properties of these same nanogranular gold films, namely their linear and nonlinear optical properties and their thermal conductivity. The linear optical properties were observed using femtosecond transient absorption spectroscopy (fTAS) and their film morphology was explored with atomic force microscopy. The switch activation mechanisms that transformed the nanogranular Au film into a resistively switchable one, clearly influenced the plasmonic effects. This implies that the plasmonic effects of the nanogranular Au film can be tuned using resistive switching and since strong plasmonic effects enhance light absorption, such films may be used for optical switching applications and modulation of optical signals in artificial optoelectronic synapses that have been engineered plasmonically. As a result of switch activation and resistive switching, stru…
author: Sibanda, Charmaine
language: en
date published: 2026-03
date modified: 2026-07-24T04:40:14Z
provider: Stellenbosch University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Stellenbosch : Stellenbosch University