Diamond crystals synthesized in the MgSiC system at high pressure high temperature (HPHT) conditions have been studied by EPR and photoluminescence. In the EPR spectra of the samples, two centers with S = 1 and S = 1/2 were detected along with substitutional nitrogen P1. Investigation of the angular dependence allowed us to establish spin Hamiltonian parameters of these centers, which turned out to be silicon containing centers KUL1 and KUL8, neutral and negatively charged silicon atom in a split-vacancy configuration, respectively. In the photoluminescence spectra of the diamond crystals there was an intense line at 737 nm corresponding to the (Si-V)− defect. X-ray irradiation, as well as UV excitation, led to an increase in relative intensities of P1 and KUL1 EPR signals, at the same time relative intensity of KUL8 decreased. Heat treatment at 773 K led to the recovery of the initial EPR spectrum. Our results confirm the hypothesis that KUL8 center is negatively charged state of Si-V defect.
|Журнал||Physica Status Solidi (A) Applications and Materials Science|
|Состояние||Опубликовано - 2015|