Electrical characterisation of emerging photo anodes suited to water dissociation with an applied bias
type: CreativeWork
description: One of the pivotal challenges of the 21st century is to develop alternative energy sources to replace the inevitable depletion of fossil fuels. One candidate for a non-polluting, abundant and renewable source of energy is sunlight. The significant challenge for the large-scale uptake of solar energy is overcoming the intermittent nature of solar radiation using energy storage methods. Synthesis of fuels from sunlight is one potential storage approach, providing the need for optimized photo-electrochemical devices and materials. The direct photovoltage of water to produce hydrogen and oxygen represents the most direct route to the synthesis of clean fuel. Recently it has been showing that technology from the microelectronics industry can be used to fabricate metal oxide semiconductors for use as photoanodes. Given that the protective oxide needs to be transparent to allow light to the photoactive material, two possible solutions are available. To have a thicker transparent conducting oxide, such as indium-tin-oxide, which would create a Schottky junction with the silicon below, or to use very thin oxides such as titanium dioxide, which when a catalyst is deposited on top creates a MOS structure. Of interest to the first option are the electrical properties of the Schottky junction in particular the barrier height, as this will dictate the current flow through to the water and drive the electrochemical reaction. For the second option to be successful, the thin oxide must not have any pinholes, i.e. to isolate the photoactive material below from the water. Atomic layer deposition is able to provide this level of conformality. A conduction mechanism study was performed and an investigation into the relationship between the stoichiometry of the titanium dioxide and the leakage current. It was shown that the level of oxygen vacancies played a key role in the level of leakage current, but a dominant conduction mechanism was not proved. Next a study into how the thickness a…
abstract: One of the pivotal challenges of the 21st century is to develop alternative energy sources to replace the inevitable depletion of fossil fuels. One candidate for a non-polluting, abundant and renewable source of energy is sunlight. The significant challenge for the large-scale uptake of solar energy is overcoming the intermittent nature of solar radiation using energy storage methods. Synthesis of fuels from sunlight is one potential storage approach, providing the need for optimized photo-electrochemical devices and materials. The direct photovoltage of water to produce hydrogen and oxygen represents the most direct route to the synthesis of clean fuel. Recently it has been showing that technology from the microelectronics industry can be used to fabricate metal oxide semiconductors for use as photoanodes. Given that the protective oxide needs to be transparent to allow light to the photoactive material, two possible solutions are available. To have a thicker transparent conducting oxide, such as indium-tin-oxide, which would create a Schottky junction with the silicon below, or to use very thin oxides such as titanium dioxide, which when a catalyst is deposited on top creates a MOS structure. Of interest to the first option are the electrical properties of the Schottky junction in particular the barrier height, as this will dictate the current flow through to the water and drive the electrochemical reaction. For the second option to be successful, the thin oxide must not have any pinholes, i.e. to isolate the photoactive material below from the water. Atomic layer deposition is able to provide this level of conformality. A conduction mechanism study was performed and an investigation into the relationship between the stoichiometry of the titanium dioxide and the leakage current. It was shown that the level of oxygen vacancies played a key role in the level of leakage current, but a dominant conduction mechanism was not proved. Next a study into how the thickness a…
author: Walsh, Adrian
language: en
keywords: Atomic layer deposition, Thin films, MOS characterisation, Ellipsometry, Metal oxide
license: http://creativecommons.org/licenses/by-nc-nd/3.0/
date published: 2018
date modified: 2026-07-24T01:48:07Z
provider: University College Cork
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University College Cork

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10468/6787