Abstract:
The effect of doping with Eu, Er, and Sm rare-earth ions on the shape of the luminescence spectrum for heterostructures with GaN/In$_x$Ga$_{1-x}$N (0.1 $< x <$ 0.4) quantum wells and from $p$-GaN$\langle$Mg$\rangle$/$n$-GaN and $p$-AlGaN/$n$-GaN junctions is investigated. The results of measurements of the electroluminescence of these structures correlate with the previous data on photoluminescence and Mössbauer spectroscopy. It is shown that it is the GaN “yellow” (5000–6000$\mathring{\mathrm{A}}$) band that plays the important role in the excitation of intracenter states in the structures with several GaN/InGaN quantum wells doped with Eu and Sm. In this case, Eu is most likely the sensitizer for Sm. Additional introduction of 3$d$ metal (Fe$^{57}$) in $p$-GaN$\langle$Mg$\rangle$/$n$-GaN:Eu results in the realization of intracenter transitions in Eu$^{3+}$: $^5D_0$$\to$$^7F_1$ (6006 $\mathring{\mathrm{A}}$), $^5D_0$$\to$$^7F_2$ (6195 $\mathring{\mathrm{A}}$), $^5D_0$$\to$$^7F_3$ (6627 $\mathring{\mathrm{A}}$), and $^5D_1$$\to$$^7F_4$ (6327 $\mathring{\mathrm{A}}$) due to the occurrence of new, efficient channels of excitation transfer to intracenter states and in the effect of Fe on the local environment of rare-earth ions including due to the $f$–$d$ hybridization enhancement.
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