Room temperature epitaxial growth of AlGaN on ZnO by pulsed laser deposition

The authors have grown Al0.1Ga0.9N films on atomically flat ZnO substrates at room temperature (RT) by pulsed laser deposition. Epitaxial growth of AlGaN at RT proceeds in the layer-by-layer mode, and the films show atomically flat stepped and terraced surfaces. On the other hand, growth at 600 degrees C proceeds three dimensionally, and the films suffer from degradation in their crystalline quality and from rough surface morphology. These results indicate that suppression of the formation of interfacial layers between AlGaN and ZnO by reducing the growth temperature is inherently important in order to take advantage of the nearly lattice-matched ZnO substrates. They have also found that high-quality AlGaN films can be obtained under highly N-rich conditions at reduced growth temperatures, which provides a striking contrast to the case of molecular beam epitaxy. (c) 2006 American Institute of Physics.