Mapping the Local Spatial Charge in Defective Diamond by Means of N- V Sensors—A Self-Diagnostic Concept

Abstract

Electrically-active defects have a significant impact on the performance of electronic devices based on wide band-gap materials such as diamond. This issue is ubiquitous in diamond science and technology, since the presence of charge traps in the active regions of different classes of diamond-based devices (detectors, power diodes, transistors) can significantly affect their performances, due to the formation of space charge, memory effects and the degradation of the electronic response associated with radiation damage. Among the most common defects in diamond, the nitrogen-vacancy (NV) center possesses unique spin properties which enable highsensitivity field sensing at the nanoscale. Here we demonstrate that NV ensembles can be successfully exploited to perform a direct local mapping of the internal electric field distribution of a graphite-diamond-graphite junction exhibiting electrical properties dominated by trap-and space-charge-related conduction mechanisms. By performing optically-detected magnetic resonance measurements, we performed both punctual readout and spatial mapping of the electric field in the active region at different bias voltages. In this novel "self-diagnostic" approach, defect complexes represent not only the source of detrimental space charge effects, but also a unique tool to directly investigate them, by providing experimental evidences on the conduction mechanisms that in previous studies could only be indirectly inferred on the basis of conventional electrical and optical characterization.

Imaging the Local Charge Environment of Nitrogen-Vacancy Centers in Diamond

“…First, we demonstrate that the characteristic splitting of the NV's magnetic resonance spectrum ( Fig. 1a), observed in ensemble NV experiments [9,14,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59], originates from its local electric environment [60]; this contrasts Typical optically-detected magnetic resonance (ODMR) spectrum of an electron-irradiated and annealed Type-Ib diamond sample (S1) at zero magnetic field. The spectrum exhibits heavy tails which cannot be reproduced by either a double Lorentzian or Gaussian (orange fit) profile.…”

“…2b, one finds that the central hyperfine resonance is split in direct analogy to the prior spectra. The most distinct of the aforementioned features -a split central resonance -has typically been attributed to the presence of lattice strain [9,[44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59]. Such strain can indeed lead to a coupling between the |m s = ±1 states, and thus split their energy levels.…”

A Quantum Defect Sees its Charged Surroundings

“…First, we demonstrate that the characteristic splitting of the NV's magnetic resonance spectrum [ Fig. 1(a)], observed in ensemble NV experiments [9,14,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], originates from its local electric environment [59]; this contrasts with the conventional picture that strain dominates the zero-field properties of these systems. Second, we introduce a chargebased model [ Fig.…”

“…The most distinct of the aforementioned features-a split central resonance-has typically been attributed to the presence of lattice strain [9,[44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]. Such strain can indeed lead to a coupling between the jm s ¼ AE1i states, and thus split their energy levels.…”

Practical Applications of Quantum Sensing: A Simple Method to Enhance the Sensitivity of Nitrogen-Vacancy-Based Temperature Sensors

“…However, many of the existing methods have drawbacks such as poor temporal and spatial resolution, low signalto-noise ratio, instability in fluorescence emission, and limited operation time. In this perspective, negatively charged nitrogen-vacancy N-V centers in diamond have attracted increasing attention thanks to their unique sensing capabilities [1,10,11]. Sensing techniques based on N-V centers in diamond can be implemented at room temperature; they are also the only technique suited for operating in extremepressure conditions [12].…”