Optical Property of GaN Single Crystals Grown by Liquid Phase Epitaxy (LPE)

概要

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The photoluminescence spectra of GaN single crystals were investigated at the temperature range of 20K to 300K. The GaN single crystals are grown using the liquid phase epitaxy technique with Na or Na-Ca flux. These crystals are grown on 3 μm GaN thin films. The photoluminescence spectra of the GaN single crystal grown by Na flux method shows a strong band edge emission at low and room temperature. The emissions from the deep levels of the Na-flux GaN were very weak at low temperature. This reveals the GaN single crystal grown in Na flux contains few impurities imported by the high temperature solution system. On the other hand, the GaN single crystal grown in the Na-Ca mixed flux system shows the donor-acceptor pair emission. The origin of the acceptor seems to be Ca or Mg included in the Ca mixed flux. The yellow luminescence from the GaN single crystal grown in the Na-Ca mixed flux was not observed even at room temperature. The acceptor impurity (Ca and/or Mg) seemed to suppress the formation of the Ga vacancies. These results were consistent with the data of secondary ion mass spectroscopy (SIMS).
Japan Society of Applied Physicsの論文
2004-02-01