Wafer Scale N‐Doped Diamond (111) with Mainly Nitrogen Spin Bath Limited Nitrogen Vacancy Coherence Times from Heteroepitexial Growth

Diamond (111) is grown heteroepitaxially on 2 00 Ir/YSZ/Si (111) wafers (YSZ=yttria-stabilized zirconia) with a diameter of 50 mm and off-cuts of up to 6°, applying plasma-enhanced chemical vapor deposition supported by bias enhanced nucleation and epitaxial lateral overgrowth. In the final growth step, a nitrogen-doped layer (N-Cap) is superimposed. In the N-Cap, a preferential orientation of nitrogen vacancy (NV) centers along the surface normal is observed, which has a T2 coherence time of 9.3 μs, which is the highest value ever reported for heteroepitaxial diamond (111). In the meantime, the T 2 dephasing time is 95 ns, which means that the T2/T 2 ratio is almost 100, while published ratios for homoepitaxial diamond are in the range 5-20. The total nitrogen concentration as measured by Time-of-Flight Secondary Ion Mass Spectrometry is determined to be 7.3 ppm, which, in combination with photoluminescence analysis, yields an NV incorporation efficiency of 0.1%.