Figure 6a,c shows the spectra of the plasmas at different pO2 just after arriving at the substrate. The spectra show a clear trend depending on pO2 for both 2*10−2 and 1*10−1 mbar total pressures. Comparison with spectra from the binary oxides and reference tables29,30 showed that the plasmas were dominated by atomic Zr lines at low pO2. Especially, the lines between 400 and 500 nm can be assigned to atomic Zr species. The relative intensity in this region decreased with increasing pO2. Simultaneously, between 500 and 600 nm bands originating from zirconia increased. With increasing oxidation, the contribution of yttria to the spectra became stronger as well. Especially, a strong YO band showed up at 597 nm. In order to compare the oxidation of the plasmas, the relative intensity of this line was determined for all pO2 after different delay times. Figure 6b,d show the results for the total pressures of 2*10−2 and 1*10−1 mbar respectively. The presence of the YO line was noted above pO2 of 1*10−4 mbar in 2*10−2 mbar total pressure, and 5*10−4 mbar in the 1*10−1 mbar case. When the plasma arrived at the substrate, the YO line was more pronounced at total pressures of 1*10−1 mbar, compared to similar pO2 in 2*10−2 mbar. However, at 2*10−2 mbar, the relative intensity of the YO still increased after arrival, while the increase hardly occurred at 1*10−1 mbar. For both total pressures, oxidation was observed at pO2 corresponding to optimal YSZ quality (5*10−3 and 5*10−4 for 0.02 and 1*10−1 mbar respectively, see Fig. 2).Figure 6Self emission spectra of the plasma at total pressures of (a) 2*10−2 and (c) 1*10−1 mbar after arriving at the substrate, respectively 6 and 20 μs after ablation. The YO line at 597 nm is indicated with a black arrow. (b,d) Show the relative intensities of the YO line at 597 nm after different delay times for total pressures of 2*10−2 and 1*10−1 mbar respectively. The color scales correspond to subfigures (a,c), the arrivial of the plasma plume at the substrate is indicated with a dashed line.