Structural properties of some transition metal nitride thin films studied using metal and N K-edge X-ray absorption spectroscopy

Transition metal nitrides (TMNs) are formed with an interstitial incorporation of N atoms in the host TM lattice. Such insertion causes an expansion of the metal lattice and the interaction force between metal atoms gets suppressed. This leads to a contraction of d-band and therefore the density of states near Fermi level increases. In this talk the focus will be on emerging applications of TMNs and our recent results on FeN and ScN thin films. In case of FeN, it was found that though Fe—N bond distances were close to the theoretically predicted values but Fe-Fe bond distances dilated due to intrinsic defects. In case of ScN, N K-edge reveals a pronounced incorporation of oxygen in metallic Sc and interstitial ScN samples but as stochiometric ScN phase begin to form, reduction of O content was evident. Complementary Sc K-edge XAS study shows distinct evolution from Sc —ScN, where an intense pre-edge feature stems from non-centrosymmetric distortion whereas, octahedral symmetry was retained in ScN samples