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Defect engineered blue photoluminescence in ZnO:Al/TiO2 heterostructures.
- Source :
- Journal of Applied Physics; 8/14/2022, Vol. 132 Issue 6, p1-11, 11p
- Publication Year :
- 2022
-
Abstract
- Tailoring the blue photoluminescence (PL) in Al-doped ZnO (AZO)/TiO<subscript>2</subscript> heterostructures is demonstrated by a controlled induction of shallow defect centers by 50 keV Ar<superscript>+</superscript>-ions. This is established by a combination of temperature dependent PL and electron paramagnetic resonance spectroscopy. The dominant blue-violet PL in an as-grown sample comprises a near band-edge emission, along with a peak associated with a radiative recombination of the electrons in shallow donor levels (Zn interstitials) and the holes from the valence band. However, the evolution of an additional yellow-green PL band at a fluence of 1 × 10<superscript>15</superscript> ions/cm<superscript>2</superscript> is governed by deep donor levels, particularly ionized oxygen vacancies. Irradiation at 1 × 10<superscript>16</superscript> ions/cm<superscript>2</superscript> further leads to the formation of Zn vacancies (shallow acceptors) owing to the development of an O-rich surface. The structural modifications of these samples have been investigated by field-emission scanning electron microscopy , transmission electron microscopy, and Rutherford backscattering. While small micro-cracks are found at a fluence of 2 × 10<superscript>16</superscript> ions/cm<superscript>2</superscript>, the formation of graded layers is obtained at the highest fluence of 5 × 10<superscript>16</superscript> ions/cm<superscript>2</superscript> owing to ballistic intermixing and diffusion of the constituents. Detailed investigation suggests that a significant amount of Ti atoms is diffused in AZO by a complete deterioration of the AZO/TiO<subscript>2</subscript> matrix at the highest fluence. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00218979
- Volume :
- 132
- Issue :
- 6
- Database :
- Complementary Index
- Journal :
- Journal of Applied Physics
- Publication Type :
- Academic Journal
- Accession number :
- 158508458
- Full Text :
- https://doi.org/10.1063/5.0096116