Local atomic configurations, energy structure, and optical properties of implantation defects in Gd-doped silica glass: An XPS, PL, and DFT study

Autor: V. Ya. Shur, D. A. Zatsepin, A. F. Zatsepin, Yu. A. Kuznetsova, N. V. Gavrilov, A. A. Esin, D. W. Boukhvalov
Rok vydání: 2019
Předmět:
Zdroj: Journal of Alloys and Compounds. 796:77-85
ISSN: 0925-8388
DOI: 10.1016/j.jallcom.2019.04.303
Popis: The KUVI-SiO2 hosts were Gd-implanted and passivated using Bonilla's stable passivation conditions. Their electronic structure was studied employing X-ray Photoelectron (XPS) and Photoluminescence (PL) spectroscopies with the onward theoretical DFT-modeling of experimentally derived scenarios for pulsed Gd-implantation into amorphous matrix. Both experiment and theory report the unfavorability of substitutional Gd-defects formation. The most probable scenario of Gd accumulation in the host-structure is Gd-interstitials with the fabrication of ≡Si–O–[Gd]3+… clusters with partial location of Gd atoms in the vicinity of Si ODC's. Tempering reduces the Nomura's bonds-switching charge-transfer mechanism in the electronic structure of KUVI-SiO2:Gd and, with a high probability, leads to fabrication of Si QDs, which have been well recognized by the PL-technique. DFT calculations confidently demonstrate relatively low energy costs required for oxygen passivation by embedded Gd and the fabrication of Si-Si bonds inside the host.
Databáze: OpenAIRE