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Journal of Physical Studies 23(3), Article 3301 [6 pages] (2019)
DOI: https://doi.org/10.30970/jps.23.3301 LUMINESCENCE OF β-Ga2O3 CRYSTALS DOPED WITH CHROMIUMA. Luchechko, V. Vasyltsiv, L. Kostyk, O. V. Tsvetkova, B. V. Pavlyk
Department of Sensor and Semiconductor Electronics, |
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The results of the investigation of the optical absorption, excitation, and emission spectra, as well as thermo-stimulated luminescence (TSL) curves, in $\beta$-Ga$_{2}$O$_{3}$ single crystals doped with chromium are presented in this work. In the absorption and excitation spectra, wide bands are observed caused by allowed transitions from the $^{4}A_{2}$ ground level to the $^{4}T_{1}$ and $^{4}T_{2}$ excited states in the chromium ions, as well as the charge transfer band, are observed in absorption and excitation spectra. The R-lines ($^{2}E\rightarrow$ $^{4}A_{2}$ transitions) and the phonon repetitions of the R-lines are observed in the luminescence spectra against the background of a broad band in the region of 680-780 nm caused by the $^{4}T_{2}\rightarrow^{4}A_{2}$ transitions in Cr$^{3+}$ ions. The main maximum in the vicinity at temperatures around 270-290 K and a series of weakly intensive maxima at higher temperatures are revealed in the TSL of the as-grown and annealed in oxygen of $\beta$-Ga$_{2}$O$_{3}$:Cr$^{3+}$ crystals. The annealing of crystals in the oxygen atmosphere leads to an increase in the chromium luminescence intensity and the amplitude of the TSL peak at 285 K. The deconvolution of the TSL curve to elementary maxima and the calculation of the activation energy of the charge carrier traps centers have been performed.
PACS number(s): 32.30.Jc; 78.55.-m; 78.60.Kn