Surface-mediated mechanisms for defect engineering in zinc oxide

The technological usefulness of a solid often depends upon the types and concentrations of the defects it contains. In semiconducting metal oxides like zinc oxide, the concentration and diffusion of oxygen point defects, like interstitials and vacancies, play a central role in various physical phenomena, such as gas sensing, bipolar switching, photoluminescence and photocatalysis. Defect engineering in metal oxides aims at manipulating material properties through controlling the defects’ type, concentration, charge, spatial distribution, and mobility. A specific challenge that inhibits performance improvement in metal oxide devices for microelectronics, photonics, and photocatalysis usages is that bulk oxygen vacancies (VO) are typically numerous and serve as carrier recombination centers or electron current scatterers. One solution suggested by our laboratory is to thermally inject highly mobile charged oxygen interstitials (Oi) through metal oxide surfaces from the gas phase to annihilate VO in the underlying bulk. Developing novel mechanisms to control such diffusion process would be crucial in tailoring material defect chemistry for real life applications. The present work demostrates two special surface-based control mechanisms for this purpose in the case of zinc oxide: near-surface electrostatics and the chemical state of surface active sites.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2017

Author dc:creator

• Li, Ming

Contributors dc:contributor

• Seebauer, Edmund G.
• Yang, Hong
• Flaherty, David W.
• Ertekin, Elif

• Defect engineering
• Surface science
• Metal oxides
• Zinc oxide
• Oxygen interstitial
• Oxygen diffusion
• Isotope gas-solid exchange

Statement dc:rights

• Copyright 2016 Ming Li

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/95585

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/95585