Pulsed laser ablation using an excimer laser of 248 nm wavelength was
applied to prepare boron nitride films, where the ablation from boron
nitride as well as elemental boron targets was studied. The growing fi
lms were bombarded by a nitrogen or a nitrogen/argon ion beam to obtai
n stoichiometric films and to investigate ion induced modifications of
structure and properties. Depending on deposition parameters the refr
active index of the boron nitride films in the visible wavelength rang
e varies between 2.5 and 1.7 and the optical energy band gap between 2
.0 and 4.5 eV. Most films were found to be completely sp(2)-bonded and
amorphous to nanocrystalline with a turbostratic microstructure. Only
boron nitride films deposited from the boron target and bombarded wit
h nitrogen/argon ions show also an absorption peak in the infrared spe
ctrum that indicates the presence of the cubic phase.