Diamond Materials

Diamond Materials for Quantum Application

23. September 2014: The DFG research group FOR 1493 “Diamond Materials and Quantum Applications” goes into its second funding period. FOR1493 is a national research consortium funded by the Deutsche Forsch-ungsgemeinschaft.

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Electrically driven single-photon source at room temperature in diamond

Single-photon sources that provide non-classical light states on demand have a broad range of applications in quantum communication, quantum computing and quantum metrology. Meanwhile, single-photon emission stimulated by optical laser excitation has been demonstrated for a large variety of single quantum systems like atoms, ions, molecules, diamond color centers and semiconductor quantum dots. However, from a technical point of view it is desirable to generate single photon emission by electrical excitation as it was successfully demonstrated for the first time in 2002 using single InAs quantum dots incorporated in a GaAs diode structure. However, a major obstacle of this approach is the requirement of cryogenic temperatures necessary for electrical operation due to the confinement of charge carriers inside the quantum dot at elevated temperatures.

In this context, we were able to design a novel diamond based p-i-n device which proved that the realization of a stable, electrically driven single-photon source from a single neutral nitrogen-vacancy center at room-temperature is feasible. By the demonstration of electroluminescence from a single, neutral NV center an additional central element was added to the quantum toolbox of diamond defects which thereby offers new opportunities in terms of integrating single-photon sources based on diamond defects into electronic control circuitry and spintronic applications for quantum communication and processing. Remarkably, the generation of electroluminescence follows kinetics fundamentally different to that of photoluminescence with intra-bandgap excitation. This phenomenon suggests that the electroluminescent process comprises of a precursor state during electron-hole recombination at the defect site which functions as a rate limiting step in consecutive reactions. A tentative explanation could be drawn from ab ignition calculations in which this additional state is attributed to a loosely bound hole in the valence band edge and a strongly bound electron at the NV center.

Our results thereby show the feasibility of generating single photon emission by electrical excitation at room temperature using single NV centers in the diamond lattice and further highlights that functional single defects can be integrated into electronic control structures, which is a crucial step towards elaborate quantum information devices.

Electrically driven single-photon source at room temperature in diamond
Nature Photonics 10.1038/NPHOTON.2012.75

N. Mizuochi 1,2, T. Makino 3,4, H. Kato 3,4, D. Takeuchi 3,4, M. Ogura 3,4, H. Okushi 3,4, M. Nothaft 5, P. Neumann 5, A. Gali 6,7, F. Jelezko 8, J. Wrachtrup 5 and S. Yamasaki 3,4

1 Graduate School of Engineering Science, Osaka University 1-3, Machikane-yama, Toyonaka-city, Osaka, 560-8531, Japan
2 JST PRESTO, 4-1-8 Honcho Kawaguchi, Saitama, 333-0012, Japan
3 Energy Technology Research Institute-National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan
4 JST CREST, 4-1-8 Honcho Kawaguchi, Saitama, 333-0012, Japan
5 3rd Physics Institute and Research Center SCoPE, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
6 Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, PO Box 49, H-1525, Hungary
7 Department of Atomic Physics, Budapest University of Technology and Economic, Budafoki ut 8, H-1111 Budapest, Hungary
8 Institut für Quantenoptik, Universität Ulm, Albert Einstein Allee 11, D-89069 Ulm, Germany