An efficient and low-cost method to create high-density nitrogen-vacancy centers in CVD diamond for sensing applications.

Authors

Prem Bahadur Karki, Wichita State University
Rupak Timalsina, University of Nebraska - LincolnFollow
Mohammadjavad Dowran, University of Nebraska-Lincoln
Ayodimeji E. Aregbesola, Wichita State University
Abdelghani Laraoui, University of Nebraska-LincolnFollow
Kapildeb Ambal, Wichita State University

Document Type

Article

Date of this Version

2023

Citation

Published (2023) Diamond and Related Materials, 140, art. no. 110472, Also in arXiv at https://arxiv.org/abs/2301.08712

Comments

Used by permission.

Abstract

The negatively charged Nitrogen-Vacancy (NV^-) center in diamond is one of the most versatile and robust quantum sensors suitable for quantum technologies, including magnetic field and temperature sensors. For precision sensing applications, densely packed NV^- centers within a small volume are preferable due to benefiting from 1/√𝑁 sensitivity enhancement (N is the number of sensing NV centers) and efficient excitation of NV centers. However, methods for quickly and efficiently forming high concentrations of NV^- centers are in development stage. We report an efficient, low-cost method for creating high-density NV^- centers production from a relatively low nitrogen concentration based on high-energy photons from Ar⁺ plasma. This study was done on type-IIa, single crystal, CVD-grown diamond substrates with an as-grown nitrogen concentration of 1 ppm. We estimate an NV^- density of ~ 0.57 ppm (57%) distributed homogeneously over 200 μm deep from the diamond surface facing the plasma source based on optically detected magnetic resonance and fluorescence confocal microscopy measurements. The created NV^-s have a spin-lattice relaxation time (T₁) of 5 ms and a spin-spin coherence time (T₂) of 4 μs. We measure a DC magnetic field sensitivity of ~ 104 nT Hz^-1/2, an AC magnetic field sensitivity of ~ 0.12 pT Hz^-1/2, and demonstrate real-time magnetic field sensing at a rate over 10 mT s^-1 using an active sample volume of 0.2 μm³.