Low temperature epitaxial growth of In0.25Ga0.75N on lattice-matched ZnO by pulsed laser deposition

Abstract

We have grown In0.25Ga0.75N films on nearly lattice-matched ZnO (0001¯) substrates with atomically flat surfaces at low substrate temperatures using pulsed laser deposition. We have found that InGaN having a stepped and terraced structure on its surface grows at low substrate temperatures. We have also found that InGaN grows in the layer-by-layer mode, even at room temperature (RT), while maintaining straight steps and atomically flat terraces from the first monolayer. This phenomenon exhibits a singular contrast to the case of RT epitaxy of GaN on ZnO, where a considerable number of defects are observed on the stepped structure of the first several layers. This difference can be attributed to a smaller lattice mismatch between InGaN and ZnO.