Abstract
Gradient nanostructured metallic materials with a gradual change of grain boundary and dislocation density display unprecedent mechanical properties. Herein, we uncover a gradient of point defects concentration and concomitant gradient bandgap (E g) narrowing in metal oxide nanoparticles processed by a combination of severe shearing and frictional sliding deformation. Using the valence electron-energy loss spectroscopy technique, we find a gradual decrease of E g from 2.93 eV in the interior to 2.43 eV at the edge of the high-pressure torsion processed ZnO flake-shaped particle. This work paves the way to strain engineering of gradient-structured metal oxide semiconductors for unique functional properties.Impact statement We uncover a gradient of oxygen vacancy concentration and concomitant bandgap narrowing in an individual metal oxide nanoparticle processed by a combination of severe shearing and frictional sliding deformation.
Original language | English |
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Pages (from-to) | 58-64 |
Number of pages | 7 |
Journal | Materials Research Letters |
Volume | 9 |
Issue number | 1 |
DOIs | |
State | Published - 2 Jan 2021 |
Externally published | Yes |
Keywords
- Bandgap
- STEM-EELS
- ZnO
- gradient-structured materials
- high-pressure torsion