We have developed a novel liquid-phase epitaxial (LPE) technique that uses Ga-Al flux to grow AlN layers on nitrided sapphire substrates. In this study, cross-sectional and plan-view images were taken using a transmission electron microscope. An edge dislocation was dominant in the LPE AlN layers; its density was approximately 5 × 10 9 cm -2. Convergent-beam electron diffraction analysis revealed that the LPE layer had Al polarity, even though the nitrided sapphire layer had N polarity. The oxygen potential in the injecting N2 gas played an important role in the polarity inversion in the LPE growth.
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