Valence band photoemission study of the Ti-Mo-N system

An experimental study of the electronic structure of Ti1-xMoxNy thin films deposited by reactive sputtering is presented. We analyze the degree of nitridation of TiNy, MoNy and Ti1-xMoxNy films in the composition range of 0 less than or equal to x less than or equal to 1 and 0.5 less than or equal to y less than or equal to 1.2. Under the deposition conditions reported in the present work, the MoNy films do not crystallize in a single fee NaCl-type of structure (B1-type). At y less than or equal to 0.71, only the y-Mo2N phase is observed while at y greater than or equal to 1 the hexagonal MoN phase is present. In good agreement with structural characterization, the valence band shape of MoNy films changes continuously from that of the y-Mo2N to that of hexagonal MoN as y increases from 0.51 to 1.17. The B1-type structure is stabilized in the MoNy films by addition of Ti. Thus, all Ti1-xMoxNy films with 0 less than or equal to x less than or equal to 0.8 and 0.5 less than or equal to y less than or equal to 1 crystallize in the rocksalt fee phase with a lattice parameter a=0.425+/-0.005 nm.