Atomic and electronic transport on surfaces and interfaces

Mikko Hakala

Atomic and electronic transport on surfaces and interfaces

Julkaisun otsikon käännös: Elektronien kuljetus pinnoilla ja rajapinnoilla

Mikko Hakala

Teknillisen fysiikan laitos

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Pintojen ja rajapintojen ominaisuudet ovat merkittävässä roolissa kehitettäessä useita teknologioita. Mikroelektronisten laitteiden kohdalla hafniumoksidi nähdään luotettavana vaihtoehtona korvaamaan piioksidi seuraavan sukupolven transistoreissa. Kuitenkin sen rakenteesta ja virheiden muodostumisesta piin rajapinnassa tiedetään varsin vähän. Vastaavasti nanokatalyysin kohdalla metalliset nanopartikkelit eristepinnoilla tarjoavat lupaavan polun luoda uusia katalyyttisesti aktiivisia materiaaleja. Mutta paljon työtä vaaditaan, jotta ymmärretään näiden partikkelien muodostumista ja kasvua pinnoille tuoduista metalliatomeista. Tässä väitöskirjassa on mallinnettu virheiden ominaisuuksia pii-hafiumoksidi-rajapinnoilla ja metallisten atomien diffuusiota alkalihalidipinnoilla. Laskut on suoritettu käyttäen tiheysfunktionaaliteoriaa (DFT). Lisäksi rajapintojen kohdalla on tutkimusta täydennetty mallintamalla elektronien kuljetusta. Tulokset ovat antaneet erinomaista tietoa tutkituista ominaisuuksista, mutta samalla näille rakenteille olemme havainneet, että tiheysfunktionaaliteoriassa käytettävien funktionaalien tarkkuutta tulee parantaa. Tätä varten olemme implementoineet tehokkaan hybridifunktionaalimenetelmän SIESTA koodiin ja osoittaneet, että tämä todella parantaa laskennallista kuvaa materiaalien ominaisuuksista.

Julkaisun otsikon käännös	Elektronien kuljetus pinnoilla ja rajapinnoilla
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Ohjaaja	Nieminen, Risto, Vastuuprofessori Foster, Adam, Vastuuprofessori
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-5513-8
Sähköinen ISBN	978-952-60-5514-5
Tila	Julkaistu - 2013
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

tiheysfunktionaaliteoria
pinnat
rajapinnat

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-60-5514-5

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title = "Atomic and electronic transport on surfaces and interfaces",

abstract = "The properties of interfaces and surfaces play a key role in the functional design of many technologies, particularly in the development of next generation micro-electronic devices and nanocatalysts. In micro-electronics, hafnia is seen as a reliable replacement for silica in modern transistors, yet little is known about its interface with silicon and probable defects formed. Similarly, the formation of metallic nanoparticles on insulators is a promising route to new catalytically active materials, but much work is needed to understand the dynamical growth of these particles on surfaces from deposited metal atoms. In this thesis we have modeled the properties of defects in silicon-hafnia interfaces and metal adatoms on alkali halide surfaces. The calculations have been performed within the density-functional theory (DFT), supported by electron transport calculations for the interface studies. Although these results have been successful in building our understanding, we have identified the need to enhance the accuracy of the standard DFT approach without sacrificing computational speed. For this we have implemented efficient hybrid functionals into the SIESTA code and shown that it indeed improves our description of critical materials' properties.",

keywords = "density-functional theory, interfaces, surfaces, exchange, tiheysfunktionaaliteoria, pinnat, rajapinnat, density-functional theory, interfaces, surfaces, exchange",

author = "Mikko Hakala",

year = "2013",

language = "English",

isbn = "978-952-60-5513-8",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

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number = "219",

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school = "Aalto University",

}

TY - BOOK

T1 - Atomic and electronic transport on surfaces and interfaces

AU - Hakala, Mikko

PY - 2013

Y1 - 2013

N2 - The properties of interfaces and surfaces play a key role in the functional design of many technologies, particularly in the development of next generation micro-electronic devices and nanocatalysts. In micro-electronics, hafnia is seen as a reliable replacement for silica in modern transistors, yet little is known about its interface with silicon and probable defects formed. Similarly, the formation of metallic nanoparticles on insulators is a promising route to new catalytically active materials, but much work is needed to understand the dynamical growth of these particles on surfaces from deposited metal atoms. In this thesis we have modeled the properties of defects in silicon-hafnia interfaces and metal adatoms on alkali halide surfaces. The calculations have been performed within the density-functional theory (DFT), supported by electron transport calculations for the interface studies. Although these results have been successful in building our understanding, we have identified the need to enhance the accuracy of the standard DFT approach without sacrificing computational speed. For this we have implemented efficient hybrid functionals into the SIESTA code and shown that it indeed improves our description of critical materials' properties.

AB - The properties of interfaces and surfaces play a key role in the functional design of many technologies, particularly in the development of next generation micro-electronic devices and nanocatalysts. In micro-electronics, hafnia is seen as a reliable replacement for silica in modern transistors, yet little is known about its interface with silicon and probable defects formed. Similarly, the formation of metallic nanoparticles on insulators is a promising route to new catalytically active materials, but much work is needed to understand the dynamical growth of these particles on surfaces from deposited metal atoms. In this thesis we have modeled the properties of defects in silicon-hafnia interfaces and metal adatoms on alkali halide surfaces. The calculations have been performed within the density-functional theory (DFT), supported by electron transport calculations for the interface studies. Although these results have been successful in building our understanding, we have identified the need to enhance the accuracy of the standard DFT approach without sacrificing computational speed. For this we have implemented efficient hybrid functionals into the SIESTA code and shown that it indeed improves our description of critical materials' properties.

KW - density-functional theory

KW - interfaces

KW - surfaces

KW - exchange

KW - tiheysfunktionaaliteoria

KW - pinnat

KW - rajapinnat

KW - density-functional theory

KW - interfaces

KW - surfaces

KW - exchange

M3 - Doctoral Thesis

SN - 978-952-60-5513-8

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Atomic and electronic transport on surfaces and interfaces

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

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