We have grown group III nitride epitaxial films on various substrates by pulsed laser deposition and investigated structural properties of the surfaces and the hetero-interfaces using grazing incidence angle X-ray reflectivity (GIXR) and atomic force microscopy (AFM). It has been found that hetero-interfaces between PLD AIN and conventional substrates such as Al2O3 and Si are quite abrupt (about 0.5 nm) probably due to a less reactive growth ambience. However, we observed a thin interfacial layer (less than 10 nm) at the hetero-interface between AIN and ( Mn,Zn)Fe2O4. The surface roughness of AIN is mainly determined by the extent of the lattice mismatch. It has been also found that the roughness at the hetero-interface between GaN and AIN formed by PLD coincides with the surface roughness of the AIN layer. (C) 2002 Elsevier Science B.V. All rights reserved.