A New Defect Center in Type Ib Diamond Inducing One Phonon Infrared Absorption: The Y Center
The other color centers traditionally responsible for one-phonon absorption (i.e., spectral absorption due to the presence of certain defects in the diamond’s lattice structure) include single isolated boron, the A center (di-nitrogen), the B center (four nitrogen atoms surrounding an atomic vacancy in the diamond lattice), the C center (single-substitutional nitrogen, N0), the X center (positively charged single-substitutional nitrogen, N+), and the D, E, and F centers, which have not been attributed to any specific defect.
After correction and normalization of the samples’ infrared spectra, and an attempt to determine the A, B, and C center nitrogen content using spectral fitting data, the researchers found that the margin of error for the C center content was at least 50%. This suggests that some absorption bands underlie the well-known single-substitutional nitrogen absorption at 1130 cm–1. For this reason, all spectra are decomposed again by progressive subtraction of the A, B, C, and X center absorptions. For 38 diamonds, this resulted in a consistent residual absorption with a relatively broad apparent maximum centered at ~1145 cm–1.
A large sample of type Ib diamonds confirmed that this new absorption system is not an artifact of the original spectral decomposition work. The authors propose to call it the Y center because it is clearly related to the single-substitutional nitrogen system of the last named one-phonon infrared absorption center, the X center.
Abstracted by Edward R. Blomgren