Formation of perfectly aligned high-density NV centers in (111) CVD-grown diamonds for magnetic field imaging of magnetic particles

Magnetic field imaging of magnetic particles using diamond sensors with nitrogen-vacancy (NV) centers has the potential to become a new prominent living-cell observation method, because of the reduction of photodamage to cells. To realize a higher signal-to-noise ratio of magnetic detection, perfectly aligned and high-density NV centers in the diamond are required because they are effective in reducing optical shot noise. In this study, diamond films were grown by microwave plasma CVD on (111) substrates. The highest NV density with a perfectly aligned NV axis of 7 x 10(17) cm(-3) was obtained with a high growth rate due to the increase of vacancies, and the reduction of the optical shot noise to 1/4 was confirmed. Moreover, magnetic field imaging with different-thickness NVs in CVD-grown diamonds showed the dependence of the magnetic field distribution pattern and SNR on the diamond film thickness. (C) 2019 The Japan Society of Applied Physics