Neutral Silicon Vacancy Centers in Undoped Diamond via Surface Control

Abstract

Neutral silicon vacancy centers (SiV 0 ) in diamond are promising candidates for quantum applications; however, stabilizing SiV 0 requires high purity, boron doped diamond, which is not a readily available material. Here, we demonstrate an alternative approach via chemical control of the diamond surface. We use low-damage chemical processing and annealing in a hydrogen environment to realize reversible and highly stable charge state tuning in undoped diamond. The resulting SiV 0 centers display optically detected magnetic resonance and bulk-like optical properties. Controlling the charge state tuning via surface termination offers a route for scalable technologies based on SiV 0 centers, as well as charge state engineering of other defects.

Fast optoelectronic charge state conversion of silicon vacancies in diamond

“…SiV centers are such an acceptor, with energy levels close to the valence band (VB) ( 10 ). We also do not observe any indication of the neutral silicon vacancy (SiV 0 ) emission at 1.31 eV ( 20 , 21 , 29 ), both under green and under pulsed near-infrared excitation at 1.55 eV. The fact that SiVs occur mainly in the negative and possibly in the doubly negative (dark) charge state is typical for high-purity samples because neutral SiVs require substantial boron (or other p-type) doping ( 20 , 30 ).…”

“…Recently, Wood et al ( 19 ) used confocal fluorescence microscopy to show that the SiV charge state can be changed by diffusing and drifting photogenerated holes such that the spatial distance of the G4V to the points of illumination is also a very relevant parameter. Several strategies have previously been proposed to control the SiV charge state, including doping ( 20 ), chemical surface treatments ( 21 , 22 ), and integration into p-i-n diodes to control the position of the quasi-Fermi level ( 23 , 24 ).…”

First-Principles Investigation of Near-Surface Divacancies in Silicon Carbide

“…One interesting question to consider is whether the presence of hydrogen in the sample may affect the stability of the VV. Considering the recent success in surface control of diamond with near-surface defects, − we suggest that a possible strategy could be to thermally pretreat the SiC sample to outdiffuse unwanted H, which had been incorporated during the growth of SiC, , before the implantation of defects. In addition, it has been recently predicted that the annealing temperature for the formation of the VV in bulk 3C-SiC is ∼1200 K, consistent with several experiments .…”

Impurity atom configurations in diamond and their visibility via scanning transmission electron microscopy imaging

“…Although these properties are promising, there is one disadvantage: the charge state is not stable in high purity diamonds. A way to mitigate this is to use hydrogen terminated diamond surfaces, which stabilize the neutral charge state of the impurity [128]. The formation energy is 6.9 eV [120].…”