Two-site diamond-like point defects as new single-photon emitters

¹ Wigner Research Center for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
² Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8., Budapest, Hungary

^a email: bodrog.zoltan@wigner.mta.hu
^b email: gali.adam@wigner.mta.hu

Published online: 25 September 2014

Abstract

In this small review, we recall two promising candidates for biomarker nanosystems, in which a two-site defect embedded in a diamond-like lattice makes a single-photon source. The two candidates are the silicon-vacancy defect in diamond, and the carbon antisite-vacancy pair in 4H silicon carbide.

These defects, which by symmetry resemble to the famous nitrogen-vacancy defect in diamond, bear an exact or nearly exact C_3v symmetry, giving them selection rules which lead their important magnetooptical properties. The embedding diamond-like crystal lattice not only determines the symmetry of two-site defects, but also ensure a nontoxic vehicle on which they reside; a definitive requirement against biomarker nanosystems.

In the silicon-vacancy case, the size of the biomarker system is also an important feature. Nanoparticles of the embedding crystal do not exceed the size of molecular clusters, in order to be able to aid measuring all types of relevant biomolecular processes.