  (111)NiO epitaxial layers are grown on c-sapphire substrates by pulsed laser
deposition (PLD) technique. Structural and morphological properties of the
films are studied using in-plane as well as out-of-plane high resolution X-ray
diffraction and atomic force microscopy techniques as functions of growth
temperature, oxygen pressure and the pulses count of the laser. The study shows
that continuous epitaxial films of thickness as low as 3 nm with high
crystalline quality, smooth surface and interface morphology can be grown by
this technique. The study also reveals the co-existence of 60{\deg}-rotated
(111) triangular domains of NiO in the film. The study also evidences the
presence of a very low density of 60-degree dislocations in these films.
Density of screw and edge dislocations are also estimated to be quite low. It
has been found that growth-temperature, oxygen partial pressure and the film
thickness can influence differently the density of various dislocation types.
These parameters are also found to affect significantly the strain developed in
the films.
