Journal Article

FZJ-2017-03942

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Oxygen partial pressure dependence of surface space charge formation in donor-doped SrTiO 321

Andrä, M. (Corresponding author)FZJ* ; Dvořák, F. ; Vorokhta, M. ; Nemšák, S.FZJ* ; Matolín, V. ; Schneider, C. M.FZJ* ; Dittmann, R.FZJ* ; Gunkel, F.FZJ* ; Müller, D.FZJ* ; Waser, R.FZJ*

2017
AIP Publ. Melville, NY

This record in other databases:  

Please use a persistent id in citations: http://hdl.handle.net/2128/14594  doi:10.1063/1.4983618

Abstract: 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 pO2-dependent surface space charge formation in donor-doped SrTiO3 in oxidizing conditions.

---

Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. Elektronische Eigenschaften (PGI-6)

Research Program(s):

1. 521 - Controlling Electron Charge-Based Phenomena (POF3-521) (POF3-521)

Appears in the scientific report 2017

---

Database coverage:
; ; ; ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

---