Oxygen partial pressure dependence of surface space charge formation in donor-doped SrTiO3

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10371412" target="_blank" >RIV/00216208:11320/17:10371412 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1063/1.4983618" target="_blank" >http://dx.doi.org/10.1063/1.4983618</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/1.4983618" target="_blank" >10.1063/1.4983618</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Oxygen partial pressure dependence of surface space charge formation in donor-doped SrTiO3

Popis výsledku v původním jazyce

In this study, we investigated the electronic surface structure of donor-doped strontium titanate. Homoepitaxial 0.5 wt.% donor-doped SrTiO3 thin films were analyzed by in situ near ambient pressure X-ray photoelectron spectroscopy at a temperature of 770 K and oxygen pressures up to 5 mbar. Upon exposure to an oxygen atmosphere at elevated temperatures, we observed a rigid binding energy shift of up to 0.6 eV towards lower binding energies with respect to vacuum conditions for all SrTiO3 core level peaks and the valence band maximum with increasing oxygen pressure. The rigid shift is attributed to a relative shift of the Fermi energy towards the valence band concomitant with a negative charge accumulation at the surface, resulting in a compensating electron depletion layer in the near surface region. Charge trapping effects solely based on carbon contaminants are unlikely due to their irreversible desorption under the given experimental conditions. In addition, simple reoxygenation of oxygen vacancies can be ruled out as the high niobium dopant concentration dominates the electronic properties of the material. Instead, the negative surface charge may be provided by the formation of cation vacancies or the formation of charged oxygen adsorbates at the surface. Our results clearly indicate a pO(2)-dependent surface space charge formation in donor-doped SrTiO3 in oxidizing conditions. (C) 2017 Author(s).

Název v anglickém jazyce

Oxygen partial pressure dependence of surface space charge formation in donor-doped SrTiO3

Popis výsledku anglicky

In this study, we investigated the electronic surface structure of donor-doped strontium titanate. Homoepitaxial 0.5 wt.% donor-doped SrTiO3 thin films were analyzed by in situ near ambient pressure X-ray photoelectron spectroscopy at a temperature of 770 K and oxygen pressures up to 5 mbar. Upon exposure to an oxygen atmosphere at elevated temperatures, we observed a rigid binding energy shift of up to 0.6 eV towards lower binding energies with respect to vacuum conditions for all SrTiO3 core level peaks and the valence band maximum with increasing oxygen pressure. The rigid shift is attributed to a relative shift of the Fermi energy towards the valence band concomitant with a negative charge accumulation at the surface, resulting in a compensating electron depletion layer in the near surface region. Charge trapping effects solely based on carbon contaminants are unlikely due to their irreversible desorption under the given experimental conditions. In addition, simple reoxygenation of oxygen vacancies can be ruled out as the high niobium dopant concentration dominates the electronic properties of the material. Instead, the negative surface charge may be provided by the formation of cation vacancies or the formation of charged oxygen adsorbates at the surface. Our results clearly indicate a pO(2)-dependent surface space charge formation in donor-doped SrTiO3 in oxidizing conditions. (C) 2017 Author(s).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

APL Materials [online]

ISSN

2166-532X

e-ISSN

—

Svazek periodika

5

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

—

Kód UT WoS článku

000402754200019

EID výsledku v databázi Scopus

2-s2.0-85029896627