1
|
Jagerová A, Mikšová R, Romanenko O, Plutnarova I, Sofer Z, Slepička P, Mistrík J, Macková A. Surface modification by high-energy heavy-ion irradiation in various crystalline ZnO facets. Phys Chem Chem Phys 2021; 23:22673-22684. [PMID: 34604878 DOI: 10.1039/d1cp02388h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Self-assembled surface nanoscale structures on various ZnO facets are excellent templates for the deposition of semiconductor quantum dots and manipulation with surface optical transparency. In this work, we have modified the surface of c-, m- and a-plane ZnO single-crystals by high-energy W-ion irradiation with an energy of 27 MeV to observe the aspects of surface morphology on the optical properties. We kept ion fluences in the range from 5 × 109 cm-2 to 5 × 1011 cm-2 using the mode of single-ion implantation and the overlapping impact mode to see the effect of various regimes on surface modification. Rutherford backscattering spectroscopy in the channeling mode (RBS-C) and Raman spectroscopy have identified a slightly growing Zn-sublattice disorder in the irradiated samples with a more significant enhancement for the highest irradiation fluence. Simultaneously, the strong suppression of the main Raman modes and the propagation of the modes corresponding to polar Zn-O vibrations indicate disorder mainly in the O-sublattice in non-polar facets. The surface morphology, analysed by atomic force microscopy (AFM), shows significant changes after ion irradiation. The c- and a-plane ZnO exhibit the formation of small grains on the surface. The m-plane ZnO forms a sponge-like surface for lower fluences and grains for the highest fluence. The surface roughness itself increases with the irradiation fluence as shown by AFM measurement as well as spectroscopic ellipsometry (SE) analysis. The damage caused by high-energy irradiation leads to non-radiative processes and suppression of the near-band-edge peak as well as the deep-level emission peak in the photoluminescence spectra. Furthermore, the refraction index n and the extinction coefficient k of irradiated samples, determined by SE, have features corresponding to the particular exciton states blurred and are slightly lower in the optical bandgap region especially for the polar c-plane ZnO facet.
Collapse
Affiliation(s)
- Adéla Jagerová
- Nuclear Physics Institute, Czech Academy of Sciences, v. v. i., 250 68 Řež, Czech Republic. .,Department of Physics, Faculty of Science, J.E. Purkinje University, 400 96 Ústí nad Labem, Czech Republic
| | - Romana Mikšová
- Nuclear Physics Institute, Czech Academy of Sciences, v. v. i., 250 68 Řež, Czech Republic.
| | - Oleksander Romanenko
- Nuclear Physics Institute, Czech Academy of Sciences, v. v. i., 250 68 Řež, Czech Republic.
| | - Iva Plutnarova
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Zdeněk Sofer
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Petr Slepička
- Department of Solid State Engineering, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Jan Mistrík
- Institute of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, 532 10 Pardubice, Czech Republic.,Centre of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, 530 02 Pardubice, Czech Republic
| | - Anna Macková
- Nuclear Physics Institute, Czech Academy of Sciences, v. v. i., 250 68 Řež, Czech Republic.
| |
Collapse
|