Combinatorial Reactive Sputtering with Auger Parameter Analysis Enables Synthesis of Wurtzite Zn₂TaN₃

Abstract

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 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 X-ray diffraction (XRD) phase screening are inconclusive, including Auger parameter analysis 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 wurtzite Zn2TaN3. Besides the formation of the new ternary nitride, we map the functional properties of Zn x Ta1–x N 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 toward changes in the materials’ short-range order and chemical state.

Atomic insights into the interaction of N2, CO2, NH3, NO, and NO2 gas molecules with Zn2(V, Nb, Ta)N3 ternary nitride monolayers

“…Specifically, the evaporation of Zn 2 N 3 and VN (or NbN or TaN) in ionized nitrogen is used for the production of Zn 2 VN 3 (or Zn 2 NbN 3 or Zn 2 TaN 3 ) compounds. 17–19 The strongest binding site for NH 3 on the Zn 2 VN 3 monolayer is shown in Fig. 4(a).…”

“…As it has been previously evidenced, various modifications of the studied Zn 2 (V, Nb, Ta)N 3 monolayers can be effectively used as a charge transport interface in solar cells with a back surface field. [17][18][19] Promising interface materials should exhibit high stability, including environmental stability, to prevent the permeation of environmental molecules that can cause energy loss when carriers pass, which, in turns, leads to a drop in carrier mobility performance. 89 Conversely, recently proposed approaches of the diffusion engineering of ions and molecules have opened new routes to enhance the stability and efficiency of solar cells.…”

“…18 Continual research on Zn 2 –V–N 3 compositions, the synthesis of a thin film of the Zn 0.65 Ta 0.35 N ternary nitride, with subsequent mapping of the functional properties of Zn x Ta 1− x N ternary nitrides, has been reported. 19 Another group of potentially stable Zn 2 V (1– x ) Nb x N 3 ternary nitride compounds has been theoretically tested; within studied concentrations, 0 ≤ x ≤ 1, the Zn 2 V 0.5 Nb 0.5 N 3 compound turned out to be the most stable structure. 20 Very recently, following the strategy of aforementioned works, a new family of stable 2D materials, Zn 2 (V, Nb, Ta)N 3 monolayers, has been predicted.…”

Advancing high-throughput combinatorial aging studies of hybrid perovskite thin films via precise automated characterization methods and machine learning assisted analysis

“…Lastly, the herein presented inert-gas workflow is ideal for integrating other techniques such as X-ray photoelectron spectroscopy (XPS) for surface analysis mapping, which would provide an even deeper understanding of materials aging behavior. 60,61…”

Prediction of Zn2(V, Nb, Ta)N3 Monolayers for Optoelectronic Applications

“…It has also been reported that 150 nm Zn–Nb–N thin films can be deposited by cosputtering from Zn and Nb targets in nitrogen plasma without intentional heating . Further, Zn x Ta 1– x N thin films have been fabricated using reactive radio frequency cosputtering of Zn and Ta targets at a low temperature of approximately 70 to 150 °C . In this work, AIMD simulations are conducted to simulate the formation of the Zn 2 (V, Nb, Ta)­N 3 monolayers, motivated by the experimental data available for thin films of these materials.…”