Electrical and Computer Engineering ETDs

Publication Date

Fall 9-11-2018

Abstract

We present density functional theory (DFT) calculations of oxygen and silver defects in a crystalline model of amorphous Ge2Se3. We studied defects arising from atomic oxygen and dioxygen, as well as interstitial silver and silver displacing germanium, following Campbell's conjecture on the mechanism of dendrite formation. For oxygen defect concentrations below 2%, we show that O2 dissociates in Ge2Se3, oxygen atoms are immobile, and oxygen atoms do not cluster. Within this model, the most preferred oxygen defect in intrinsic Ge2Se3 is Ge-O-Ge bridge. We conclude that oxygen defects will not severely alter the electrical properties of Ge2Se3. Our results on silver defects in Ge2Se3 agree with and extend previous work using a similar model; the two most preferred silver defect types are intralayer silver interstitial and silver displacement of germanium. We also studied the interaction between silver defects and the most preferred oxygen defect. We learned that discounting the highest defect concentrations, oxygen defects will not severely change the behavior of silver defects in Ge2Se3, but it will inhibit the formation of Ag-Ge dimers.

Keywords

oxygen, defect, Ge2Se3, silver, memristor, DFT

Document Type

Thesis

Language

English

Degree Name

Electrical Engineering

Level of Degree

Masters

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Marek Osinski

Second Committee Member

Mark Gilmore

Third Committee Member

Arthur Edwards

Fourth Committee Member

Susan Atlas

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