Orientation Dependence of Cathodoluminescence and Photoluminescence Spectroscopy of Defects in Chemical-Vapor-Deposited Diamond Microcrystal

Abstract

Point defects, impurities, and defect–impurity complexes in diamond microcrystals were studied with the cathodoluminescence (CL) spectroscopy in the scanning electron microscope, photoluminescence (PL), and Raman spectroscopy (RS). Such defects can influence the directions that microcrystals are grown. Micro-diamonds were obtained by a hot-filament chemical vapor deposition (HF CVD) technique from the methane–hydrogen gas mixture. The CL spectra of diamond microcrystals taken from (100) and (111) crystallographic planes were compared to the CL spectrum of a (100) oriented Element Six diamond monocrystal. The following color centers were identified: 2.52, 2.156, 2.055 eV attributed to a nitrogen–vacancy complex and a violet-emitting center (A-band) observed at 2.82 eV associated with dislocation line defects, whose atomic structure is still under discussion. The Raman studies showed that the planes (111) are more defective in comparison to (100) planes. What is reflected in the CL spectra as (111) shows a strong band in the UV region (2.815 eV) which is not observed in the case of the (100) plane.

Comparison and Selection of Data Processing Methods for the Application of Cr3+ Photoluminescence Piezospectroscopy to Thermal Barrier Coatings

“…Cr 3+ photoluminescence piezospectroscopy is not the only spectromechanical method. Other techniques, such as cathodoluminescence spectroscopy [30,31], Eu 3+ photoluminescence piezospectroscopy [11,32], and micro-Raman spectroscopy [33][34][35][36][37][38], have been broadly applied to the stress/strain analyses of different materials and structures. Fitting functions, such as Lorentzian, Gaussian, and Psd-Voigt functions, have been used to identify the positions and intensities of the characteristic peaks in the spectra detected from samples with external or internal stress.…”

Gemological Characteristic Difference between Colorless CVD Synthetic Diamonds and Natural Diamonds

“…Absorption spectra of faceted synthetic diamonds in the middle-infrared and near-infrared regions have no obvious absorption. An obvious carbon intrinsic peak at 1332 cm −1 is caused by the vibration of the sp 3 hybrid orbital of carbon atom [ 24 , 25 ]. In addition to this characteristic peak, there is no other characteristic peak in faceted diamonds.…”

Optimal Data Processing Method for the Application of Eu3+ Photoluminescence Piezospectroscopy in Thermal Barrier Coatings

“…Eu 3+ photoluminescence piezospectroscopy is not the only spectromechanical technique. Others, including Ce 3+ photoluminescence and [34], Cr 3+ photoluminescence piezospectroscopy, [14,23,35,36], cathodoluminescence spectroscopy [37,38], and micro-Raman spectroscopy [39][40][41][42][43][44], were also broadly applied to stress-strain analyses for different materials and structures. Data processing methods (Lorentzian, Gaussian, pseudo-Voigt (Psd-Voigt) functions, and the barycenter method) were used to identify the positions and intensities of the characteristic peaks in the spectra taken from samples with external or internal stress.…”