Epitaxial GaN thin films prepared by polymer-assisted deposition

Epitaxial GaN thin films have been deposited on (0001) sapphire substrates by a chemical solution approach of polymer-assisted deposition. The films are smooth with no detectable cracks or pores, as observed by scanning electron microscopy and atomic force microscopy. Microstructural studies by X-ray diffraction and transmission electron microscopy show that the GaN films have a hexagonal structure with an epitaxial relationship between the film and the substrate of (0001) _GaN||(0001) _Al203 and [112̄0] _GaN||[101̄0] _Al203. The films with a room temperature resistivity of around 0.13 ω · cm exhibit photoluminescence characteristic of wurtzite hexagonal GaN.