Tuning Band Alignment Using Interface Dipoles at the Pt/Anatase TiO₂ Interface
Takashi Tachikawa1,2, Makoto Minohara3, Yasuyuki Hikita1
1Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
Advanced Materials (Deerfield Beach, Fla.)
|October 28, 2015
Summary
Schottky barrier heights at platinum/titanium dioxide junctions were tuned by over 0.8 eV using a thin lanthanum aluminum oxide layer. This advance enables dipole engineering for advanced metal/oxide interfaces.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Surface Science
Background:
- Schottky barrier height (SBH) is crucial for metal-semiconductor contact performance.
- Controlling SBH is essential for optimizing electronic devices.
- Interface engineering offers a pathway to tune SBH.
Purpose of the Study:
- To investigate the modulation of Schottky barrier heights at Pt/TiO2 (001) junctions.
- To explore the effect of inserting ultrathin LaAlO3 layers on electronic properties.
- To demonstrate the potential of dipole engineering at metal/oxide interfaces.
Main Methods:
- Fabrication of Pt/TiO2 (001) heterostructures with inserted LaAlO3 layers (<1 nm).
- Characterization of electronic properties, likely including measurements of Schottky barrier heights.
- Analysis of structural properties to understand interface stability and electric field effects.
Main Results:
- A significant modulation of Schottky barrier heights (over 0.8 eV) was achieved by inserting LaAlO3.
- The large electric field within the LaAlO3 layer was stabilized by maintaining in-plane lattice symmetry.
- Demonstrated feasibility of dipole engineering at polycrystalline metal/binary oxide interfaces.
Conclusions:
- Ultrathin LaAlO3 insertion effectively tunes SBH at Pt/TiO2 junctions.
- Preservation of lattice symmetry is key to stabilizing the interfacial electric field.
- Dipole engineering is a versatile strategy for functional metal/oxide interfaces.
