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Journal of Physical Studies 22(1), Article 1602 [7 pages] (2018)
DOI: https://doi.org/10.30970/jps.22.1602 THERMALLY STIMULATED LUMINESCENCE AND THERMALLY STIMULATED DEPOLARIZATION CURRENTS IN MgGa2O4 SPINELSO. P. Kravets, R. M. Lys, O. V. Tsvetkova, A. P. Luchechko, B. V. Pavlyk
Department for Sensor and Semiconductor Electronics, Ivan Franko National University of Lviv, |
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Polycrystalline ceramics samples of MgGa$_{2}$O$_{4}$, MgGa$_{2}$O$_{4}$: Mn$^{2+}$ and MgGa$_{2}$O$_{4}$: Mn$^{2+}$, Eu$^{3+}$ were synthesized by the high-temperature solid-state reaction method. X-ray diffraction measurements confirmed the spinel phase of obtained samples with a small amount of $\beta$-Ga$_{2}$O$_{3}$ phase ($\sim$4 \%). X-ray luminescence measurements have been carried out at the liquid nitrogen temperature. A nominally pure MgGa$_{2}$O$_{4}$ sample exhibits an intense matrix emission in the UV and ``blue'' spectral regions. Doping with Mn$^{2+}$ ions leads to the appearance of an intense emission band around 500 nm. A weak emission of Eu$^{3+}$ ions was observed in the ``red'' spectral region for the MgGa$_{2}$O$_{4}$ sample co-doped with Mn$^{2+}$ and Eu$^{3+}$ ions. The measurements of thermally stimulated depolarization currents (TSDC) and thermally stimulated luminescence (TSL) were carried out for all these magnesium gallate samples. The TSDC and TSL curves were deconvoluted onto the elementary temperature peaks using the thermal elimination method. The analysis of obtained results exhibits the existence of several types of defects in the MgGa$_{2}$O$_{4}$ spinel structure. Maximums assigned to different types of cation vacancies and their complexes have been identified. Doping MgGa$_{2}$O$_{4}$ with Mn$^{2+}$ ions amplifies TSDC and TSL signals by an order of magnitude. Moreover, additional maxima were found in the TSDC curves of the MgGa$_{2}$O$_{4}$: Mn$^{2+}$ sample. Co-doping MgGa$_{2}$O$_{4}$ with Mn$^{2+}$ and Eu$^{3+}$ ions results in the amplification of the TSDC signal by an order of magnitude and doubles the TSL signal with respect to the MgGa$_{2}$O$_{4}$: Mn$^{2+}$ sample.
PACS number(s): 61.05.cp, 77.22.Ej, 78.40.Fy, 78.60.Kn, 78.70.En