Ultrafast electronic readout of diamond nitrogen–vacancy centres coupled to graphene

Abstract

Non-radiative transfer processes are often regarded as loss channels for an optical emitter 1 because they are inherently difficult to access experimentally. Recently, it has been shown that emitters, such as fluorophores and nitrogen-vacancy centres in diamond, can exhibit a strong non-radiative energy transfer to graphene [2][3][4][5][6] . So far, the energy of the transferred electronic excitations has been considered to be lost within the electron bath of the graphene. Here we demonstrate that the transferred excitations can be read out by detecting corresponding currents with a picosecond time resolution 7,8 . We detect electronically the spin of nitrogen-vacancy centres in diamond and control the non-radiative transfer to graphene by electron spin resonance. Our results open the avenue for incorporating nitrogen-vacancy centres into ultrafast electronic circuits and for harvesting non-radiative transfer processes electronically.With the advancement of nanoscale photonics research it has become increasingly desirable to combine optical systems with electric circuits to create optoelectronic devices that can be miniaturized and integrated into chips. To this end, we can take advantage of the excellent optical and electronic properties of graphene 9 , which include good photodetection capabilities 8,10-15 , efficient energy absorption 3 and strong light-matter interactions at the nanoscale 16,17 . In particular, it has been reported recently that, because of graphene's specific properties, the near-field interaction between light emitters and graphene is greatly enhanced as compared to that of conventional metals 2-6 . This interaction manifests itself, for example, in a 100-fold enhancement of the excited-state decay rate of emitters placed 5 nm away from graphene as compared to the spontaneous emission of the emitter. The physical mechanism behind the interaction is the creation of an electron-hole pair in graphene through non-radiative energy transfer (NRET) from the emitter dipole 18 . The NRET process to graphene has been demonstrated to have an efficiency of nearly 100% when the emitter is less than 10 nm away from the graphene sheet 3 , which makes graphene an ideal material to detect electronically the optical properties of nearby emitters 6 . NRET has been studied extensively for fundamental as well as for biosensing applications. However, a fast energy transfer has not yet been observed because of quenching of the optical signal for short graphene-emitter distances. In contrast, an electronic readout of the NRET enables studies on fast energy processes. Moreover, if the transferred energy can be collected, as we show in this work, new ways for energy harvesting and biosensing can be implemented.We take advantage of the highly efficient NRET process to read out electronically, for the first time, the optical excitation of nitrogen-vacancy (NV) centres in diamond nanocrystals. To this end, we used graphene for the extraction of the excited-state energy of NV centres and converted it into a measurable ...

Near‐Field Energy Transfer between a Luminescent 2D Material and Color Centers in Diamond

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“…The linear Dirac-like dispersion and the associated constant high carrier velocity promise the realization of ultrafast devices in electronics2, optics3 or even q-bits based on nitrogen vacancies4. The ultra-short timescales involved, <1 ps, provide stringent requirements on material properties.…”

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