Study of GaN : Eu³⁺  Thin Films Deposited by Metallorganic Vapor-Phase Epitaxy

Using metallorganic vapor-phase epitaxy, thin films of gallium nitride activated by Eu³⁺(GaN : Eu³⁺) have been deposited on sapphire substrates at atmospheric pressure. Luminescence from Eu³⁺ ions in GaN has been investigated using photoluminescence (PL) and PL excitation spectroscopy. Experimental results show that Eu³⁺ ions are excited via energy transfer from the host. Analyses of the observed emission and excitation spectra indicate occupancy of multiple sites in the nitride lattice. Using a pulsed laser source, variation of emission intensity with increasing excitation intensity has also been examined. The possibility of emission saturation at high excitation intensity is discussed from the perspective of application in light-emitting diode sources.