  The discovery of new functional materials is one of the key challenges in
materials science. Combinatorial high-throughput approaches using reactive
sputtering are commonly employed to screen unexplored phase spaces. During
reactive combinatorial deposition the process conditions are rarely optimized,
which can lead to poor crystallinity of the thin films. In addition, sputtering
at shallow deposition angles can lead to off-axis preferential orientation of
the grains. This can make the results from a conventional structural phase
screening ambiguous. Here we perform a combinatorial screening of the Zn-Ta-N
phase space with the aim to synthesize the novel semiconductor Zn2TaN3. While
the results of the XRD phase screening are inconclusive, including chemical
state analysis mapping in our workflow allows us to see a very clear
discontinuity in the evolution of the Ta binding environment. This is
indicative of the formation of a new ternary phase. In additional experiments,
we isolate the material and perform a detailed characterization confirming the
formation of single phase WZ-Zn2TaN3. Besides the formation of the new ternary
nitride, we map the functional properties of ZnxTa1-xN and report previously
unreported clean chemical state analysis for Zn3N2, TaN and Zn2TaN3. Overall,
the results of this study showcase common challenges in high-throughput
materials screening and highlight the merit of employing characterization
techniques sensitive towards changes in the materials' short-range order and
chemical state.
