The Effect of Surface Treatment on Structural Properties of CVD Diamond Layers with Different Grain Sizes Studied by Raman Spectroscopy

Abstract

Extensive Raman spectroscopy studies combined with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) measurements were performed to investigate structural and chemical changes in diamond layers deposited by chemical vapour deposition (CVD) upon post-growth treatment with hydrogen. The aim of this study is to characterize the changes in micro-structural properties of diamond layers with different grain sizes and different contents of sp2 carbon phase. Hydrogenation or oxidization of diamond layer surface is often performed to modify its properties; however, it can also strongly affect the surface structure. In this study, the impact of hydrogenation on the structure of diamond layer surface and its chemical composition is investigated. Owing to their polycrystalline nature, the structural properties of CVD diamond layers can strongly differ within the same layer. Therefore, in this project, in order to compare the results before and after hydrogen treatment, the diamond layers are subjected to Raman spectroscopy studies in the vicinity of a T-shape marker fabricated on the surface of each diamond layer studied.

Impact of Methanol Concentration on Properties of Ultra-Nanocrystalline Diamond Films Grown by Hot-Filament Chemical Vapour Deposition

“…The remaining components of the Raman spectra, which are associated with the nondiamond phase, differ essentially from the results already reported for nanocrystalline diamond [13,31,32] These works prove that the sp 2 fraction in nanocrystalline diamond is a mixture of amorphous carbon and trans-polyacetylene (t-Pa) macromolecules. The statement was supported by the observed Raman spectra, in which the graphitic D and G bands around 1350 and 1570 cm −1 were accompanied with t-Pa bands around 1150 and 1480 cm −1 .…”

“…The position of the d nc peak coincided with the vibrational density of states (VDOS) of diamond at 146 meV (1175 cm −1 ) and 156 meV (1260 cm −1 ) [28][29][30]. The remaining components of the Raman spectra, which are associated with the nondiamond phase, differ essentially from the results already reported for nanocrystalline diamond [13,31,32] These works prove that the sp 2 fraction in nanocrystalline diamond is a mixture of amorphous carbon and trans-polyacetylene (t-Pa) macromolecules. The state- The d nc band was Raman inactive in the bulk diamond.…”

XPS analysis of molecular contamination and sp2 amorphous carbon on oxidized (100) diamond

“…Voigt functions, in the form of a Gaussian-Lorentzian product were applied for all fits. Although several groups make mention of constraining the FWHM for all C1s peak deconvolutions to about 1 eV [19,33,34], we find here that the residual standard deviation (STD) is only minimized when the FWHM for the sp 3 C peak is roughly 0.6 eV and constrained within 0.6-0.7 eV. FWHM values for all other chemical species were constrained to within 1.30-1.6 eV.…”

Effect of Titanium and Molybdenum Cover on the Surface Restructuration of Diamond Single Crystal during Annealing

“…It is commonly accepted that the C 1s line of diamond is a symmetric Gaussian-shaped peak located near 285 eV [ 42 ]. However, the shape of the line and its position can vary depending on structural defects [ 43 ], polishing [ 44 ], and surface functionalization [ 45 ]. The C 1s spectra measured for the D-100 and D-111 faces are complex and asymmetric ( Figure 3 a,b).…”