Effect of ultraprecision polishing techniques on coherence times of shallow nitrogen-vacancy centers in diamond

Abstract

We investigate the correlation between surface roughness and corresponding T2 times of nearsurface nitrogen-vacancy centers (~7 nm/ 5 keV implantation energy) in diamond. For this purpose we compare five different polishing techniques, including both purely mechanical as well as chemical mechanical approaches, two different substrate sources (Diam2tec and Element Six) and two different surface terminations (O-and H-termination) during nitrogen-vacancy forming. All coherence times are measured and compared before and after an oxygen surface treatment at 520 °C.We find that the coherence times of shallow nitrogen-vacancy centers are surprisingly independent of surface roughness. * to ease comparison, all 2 times in this paragraph have been corrected for their implantation depth and dynamical decoupling 14 order, assuming a 2 rise of 2 with surface distance [ 15 ] and a 1 2 ⁄ scaling with the number of decoupling pulses [ 15-17 ].

Diamond—the ultimate material for exploring physics of spin-defects for quantum technologies and diamondtronics

“…Braunbeck et al, reported that NV spin coherence times are independent of the surface finish. This result suggests that intrinsic sub-surface defects are playing a larger role in decoherence than the surface itself [236]. In contrast to NV center, SiV center emits a very narrow ZPL, typically less than 6 nm width at room temperature.…”

Diamond surface engineering for molecular sensing with nitrogen—vacancy centers

“…In contrast, Braunbeck et al studied the impact of mechanical polishing and etching techniques on coherence times for shallow emitters and found minimal correlation with surface roughness. 275 These findings suggest that the particular method of preparing flat diamond surfaces (i.e., etching, polishing, etc.) likely has a strong influence on the chemical termination.…”

Fluorine-terminated diamond (110) surfaces for nitrogen-vacancy quantum sensors

“…When changing the H to the oxygen (O), fluorine (F) or nitrogen (N) with electronegativity higher than carbon, the dipole moment directed away from the diamond surface will be set up, and the diamond surfaces exhibit positive electron affinity (PEA). The experimental studies have showed that O-terminated [24][25][26] and F-terminated [27] diamond (100) surfaces can keep the negative charge state of shallow NV centers and increase the fluorescence intensity. However, for O-terminated nanodiamonds, blinking states (temporary intermittency in fluorescence) of NV centers was observed [28].…”