Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO3

Yangyang Li, Qingxiao Wang, Ming An, Kun Li, Nimer Wehbe, Qiang Zhang, Shuai Dong, Tom Wu

Research output: Contribution to journalArticle

Abstract

Metal/oxide interfaces are ubiquitous in a wide range of applications such as electronics, photovoltaics, memories, catalysis, and sensors. However, there have been few investigations dedicated to the nanoscale structural and chemical characteristics of these buried interfaces. In this work, the metal/oxide interface between Ti and SrTiO3 (STO) is examined as a prototypical system using high-resolution scanning transmission electron microscopy and electron energy loss spectroscopy. An atomic-thin Ti2O3-like layer at the Ti/STO interface prepared at room temperature is discovered, and first-principles calculations predict a metallic band structure of this 2D electron system. As a universal feature of such interfaces prepared at different temperatures, near the interface nanoscale oxygen-deficient domains and continuous modulation of Ti oxidation states are found. Overall, these results directly reveal complex chemical and valence evolutions at the metal/oxide interfaces, providing microscopic insights on such heterostructures.

Original languageEnglish (US)
Article number1600201
JournalAdvanced Materials Interfaces
Volume3
Issue number17
DOIs
StatePublished - Sep 6 2016

Keywords

  • SrTiO
  • electron energy loss spectrum
  • first-principles calculation
  • interfaces
  • oxygen vacancies

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering

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