Surface modification and stability of detonation nanodiamonds in microwave gas discharge plasma

Abstract

Detonation nanodiamonds (DND), with low hydrogen content, were exposed to microwave plasma generated in pure H 2 , N 2 , and O 2 gases and their mixtures, and investigated using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. Considerable alteration of the DND surface was observed under the plasma conditions for all used gases, but the diamond structure of the DND particle core was preserved in most cases. The stabilizing effect of H 2 in H 2 /N 2 and H 2 /O 2 binary gas plasmas on the DND structure and the temperature-dependent formation of various CNH x surface groups in N 2 and H 2 /N 2 plasmas were observed and discussed for the first time. DND surface oxidation and etching were the main effects of O 2 plasma, whereas the N 2 plasma led to DND surfaces rich in amide groups below 1073 K and nitrile groups at higher temperatures. Noticeable graphitization of the DND core structure was detected only in N 2 plasma when the substrate temperature was above 1103 K.

Early stages of polycrystalline diamond deposition: laser reflectance at substrates with growing nanodiamonds

“…8 However, under mild conditions similar to those used in this work, incubation has never been corroborated (to the best of our knowledge). 47,48…”

“…8 However, under mild conditions similar to those used in this work, incubation has never been corroborated (to the best of our knowledge). 47,48 Quantitative results are obtained by non-linear least-square tting of ( 15) with the values v d = 0.6 nm min −1 , n p = 2.41, n g = 1, and l 0 = 532 nm and tting parameters n 2D , a 0 , and V 0 . The tting ranges are manually adjusted and are listed in Table 1.…”

Tribological and Grinding Properties of Spherical Diamond Grown on a Rough Discontinuous Surface

“…Meanwhile, the high G-peak at 1572.2 cm −1 might be a Raman scattering caused by the sp 2 carbon bond, confirming a high degree of misalignment with respect to the diamond Raman peak. It was noted that characteristic peaks of varying intensity were also present in the 1650~1700 cm −1 region, which could be attributed to the sp 2 hybridized carbon [27] and the C=O group [28]. However, the object of detection was inorganic and there were no oxygenated compounds involved in the deposition reaction, thus it could be determined that the Raman peaks were not caused by C=O groups.…”

Effects of microwave oxygen plasma treatments on microstructure and Ge-V photoluminescent properties of diamond particles*

“…Also, microwave oxygen plasma treatment can control the termination state of the diamond surface, thereby enhancing the Si-V PL intensity. [25,26] Compared with thermal oxidation, microwave oxygen plasma treatment is mild and can be applied to the samples with different requirements by adjusting parameters.…”