Multi-Frequency Light Sources Based on CVD Diamond Matrices with a Mix of SiV and GeV Color Centers and Tungsten Complexes.

Recently, nanodiamonds with negatively charged luminescent color centers based on atoms of the fourth group (SiV, GeV) have been proposed for use as biocompatible luminescent markers. Further improvement of the functionality of such systems by expanding the frequencies of the emission can be achieved by the additional formation of luminescent tungsten complexes in the diamond matrix. This paper reports the creation of diamond matrices by a hot filament chemical vapor deposition method, containing combinations of luminescing Si-V and Ge-V color centers and tungsten complexes.

Duo Emission of CVD Nanodiamonds Doped by SiV and GeV Color Centers: Effects of Growth Conditions.

The investigation of the hot filament chemical vapor deposition nanodiamonds with simultaneously embedded luminescent GeV and SiV color centers from solid sources showed that both the absolute and relative intensities of their zero-phonon lines (at 602 and 738 nm) depend on nanodiamond growth conditions (a methane concentration in the CH/H gas mixture, growth temperature, and time). It is shown that a controlled choice of parameters of hot filament chemical vapor deposition synthesis makes it possible to select the optimal synthesis conditions for tailoring bicolor fluorescence nanodiamond labels for imaging biological systems.

Effect of Reactive Ion Etching on the Luminescence of GeV Color Centers in CVD Diamond Nanocrystals.

The negatively charged germanium-vacancy GeV color centers in diamond nanocrystals are solid-state photon emitters suited for quantum information technologies, bio-sensing, and labeling applications. Due to the small Huang-Rhys factor, the GeV-center zero-phonon line emission is expected to be very intensive and spectrally narrow. However, structural defects and the inhomogeneous distribution of local strains in the nanodiamonds result in the essential broadening of the ZPL.

Low-strain heteroepitaxial nanodiamonds: fabrication and photoluminescence of silicon-vacancy colour centres.

Nanodiamonds with the 'diamond' 1332.5 cm(-1) Raman line as narrow as 1.8 cm(-1) have been produced by reactive ion etching in oxygen plasma of heteroepitaxial diamond particles grown by microwave plasma enhanced chemical vapour deposition (MWPECVD) on silicon.

Ordered porous diamond films fabricated by colloidal crystal templating.

We have developed a colloidal crystal templating method for preparation of diamond films with 2D and 3D ordered porous structures. The technological process involved breaks down into (a) impregnation into the pores of silica colloidal crystal (opal) films of detonation nanodiamond (DND) particles from their hydrosol; (b) microwave plasma-enhanced chemical vapor deposition (MWPECVD) regrowth with diamond of pores with high DND filling; (c) Ar(+) ion dry etching of fragments of shells of coalesced diamond crystallites which form in the course of MWPECVD on the surface of the SiO(2) beads making up the outer surface of a film and (d) wet etching of the SiO(2) template in aqueous HF solution. The final samples are either connected to the substrate or free-standing films of various thicknesses having 2D or 3D ordered porous structures.

Micro-Raman Mapping of 3C-SiC Thin Films Grown by Solid-Gas Phase Epitaxy on Si (111).

A series of 3C-SiC films have been grown by a novel method of solid-gas phase epitaxy and studied by Raman scattering and scanning electron microscopy (SEM). It is shown that during the epitaxial growth in an atmosphere of CO, 3C-SiC films of high crystalline quality, with a thickness of 20 nm up to few hundreds nanometers can be formed on a (111) Si wafer, with a simultaneous growth of voids in the silicon substrate under the SiC film. The presence of these voids has been confirmed by SEM and micro-Raman line-mapping experiments.

Emitting a-SiO(x)(Er) films and a-SiO(x)(Er)/a-Si:H microcavities doped with Er by remote magnetron sputtering technique.

We have developed the technique of growing amorphous a-SiO(x)(Er) films and a-SiO(x)(Er)/a-Si:H multilayer structures based on spatially separating the processes of the decomposition of an oxygen-silane gas mixture in an rf glow discharge plasma and remote magnetron sputtering of an Er target. This approach allows us to control independently the film deposition rate, the Er-ion concentration and its depth distribution in the film. Time-resolved photoluminescence measurements have shown that films and planar microcavities with an Er-doped active layer exhibit internal quantum efficiency for Er ion emission of ∼75%.

Polarization splitting of optical resonant modes in a-Si:H/a-SiO(x):H microcavities.

We present experimental and theoretical results on polarization splitting of optical resonant modes in a-Si:H/a-SiO(x):H microcavities. It is shown experimentally that the splitting sign and value can be controlled by varying the active layer thickness. The polarization splitting achieved in the microcavities is about 8 meV owing to a large optical contrast, which is the ratio of film refractive indices in the distributed Bragg reflectors.