Über den Effekt von Stickstoffsubstitution auf die strukturellen Eigenschaften von polykristallinem Galliumoxid und die elektrische Leitfähigkeit von amorphen Lanthangallat Dünnschichten

摘要

The ammonolysis of b-gallium oxide (b-Ga2O3) was analyzed systematically in order to obtain information about structural aspects and thermodynamics of the system Ga2O3-GaN. This study focuses on the possible formation of gallium oxynitride (GaON) intermediates and the soluibility of nitrogen in the oxide sublattice and its resulting effects on the crystal structure. This was realized by employing ex situ X-Ray and neutron diffraction techniques (XRD, ND). In an additional set of experiments we prepared nitrogen containing lanthanum gallate (LaGaO3) layers by means of Pulsed Laser Deposition (PLD) in presence of nitrogen species. Those layers were deposited on single crystalline aluminum oxide (Al2O3) and yttria stabilized zirconia (YSZ) substrates. Electrochemical impedance spectroscopy (EIS) and a modified Hebb-Wagner DC-setup were used to determine the electrical conductivities of the lanthanum gallium oxynitride (LaGaOxNy)-layers. The observation of electrochemical properties of the system leads to information about the underlying defect chemistry. The presence of nitrogen in the material is confirmed by means of electron probe micro analysis (EPMA). Structural and morphological aspects are monitored with ex situ XRD-methods.