Effect of boron doping on luminescent properties of silicon--vacancy and germanium--vacancy color centers in diamond particles obtained by chemical vapor deposition

Abstract

The effect of doping with boron on the luminescent properties of diamond particles synthesized by Hot Filament Chemical Vapor Deposition technique with color centers embedded during the growth process has been studied. It is shown that at low boron doping level, the photoluminescence intensity of a narrow zero-phonon line of the silicon-vacancy color center (738.2 nm) demonstrates a strong dependence on the concentration of boron atoms at the sites of the diamond lattice. The dependence of the intensity of a broad photoluminescence band in the wavelength range 520-800 nm on the concentration of boron atoms in the gas mixture in the range from 14 to 64000 ppm has been analyzed. The Raman scattering spectra of the obtained particles have been studied. At the concentration of boron atoms in the gas mixture up to 1540 ppm, the Raman scattering spectra of diamond particles practically do not change when the boron concentration is varied. At high boron doping level, the diamond band in the Raman spectra exhibit a spectral response typical of the Fano resonance. Keywords: diamond particles, color centers, boron doping, photoluminescence, chemical vapor deposition.

Multifunctional Core/Shell Diamond Nanoparticles Combining Unique Thermal and Light Properties for Future Biological Applications

“…The same phenomenon was observed earlier in Ref. [23]. Figure 5 demonstrates the Raman and PL spectra of a single core/shell diamond nanoparticle consisting of a heavily boron-doped diamond core of about 800 nm in diameter covered by a diamond shell with embedded luminescent SiV color centers of ~500 nm in thickness.…”

“…It can be seen that the asymmetric spectral response typical of the Fano resonance dominates the spectrum of the BNDs. The appearance of such a feature in the Raman spectrum is a signature of doping diamonds with boron at concentrations in the gas mixture above several tens of thousands ppm, which leads to a change in the structure of the diamond crystal lattice [3,23,[28][29][30]. The increase in the degree of boron doping leads to a shift in the Raman band of diamond from ~1332.5 cm −1 to low frequencies down to 1300 cm −1 and an increase in its FWHM from 6 cm −1 to ~20 cm −1 .…”

“…At the first stage, the growth of diamond particles (diamond core) of about 800-1100 nm in size was carried out, during which doping with boron occurred by introducing diborane (B 2 H 6 ) into the gas mixture. The boron-doped nanodiamonds (BNDs), used as the cores, were synthesized by the HFCVD method with parameters we previously determined [23]. Briefly, the substrate temperature was 800 • C, the temperature of the tungsten coil was 2000-2200 • C, the pressure in the reactor chamber was 48 Torr, the hydrogen flow rate was 480 sccm, the methane concentration was 4%, and the growth time was about 3 h. For the synthesis of highly absorbing BNDs, the ratio of boron atoms to carbon atoms (B/C) in the diborane-methane mixture was 64,000 ppm.…”

“…The idea to combine the advantages of the diamond nanocrystals doped by the different atoms in order to create a novel multifunctional heterostructure for efficient local photoinduced hyperthermia therapy, whilst also controlling the temperature of the tissue and labeling it with a fluorescent marker, looks very attractive [22]. At least two attempts to synthesize diamond nanocrystals doped with boron, silicon, and germanium are known [5,23]. In the first case [5], commercially available boron-doped nanodiamonds (BNDs) with an average size of 100 nm were implanted with silicon for optical temperature sensing.…”

“…In the first case [5], commercially available boron-doped nanodiamonds (BNDs) with an average size of 100 nm were implanted with silicon for optical temperature sensing. In the second case [23], BNDs were synthesized using the hot filament chemical vapor deposition (HFCVD) technique with GeV and SiV color centers embedded during the growth process.…”