Coloured diamond

摘要

A diamond layer of single crystal CVD diamond which is colored, preferably which has a fancy color, and which has a thickness of greater than 1 mm.

主权项

1. A method of producing a coloured single crystal diamond layer comprising:
selecting a single crystal diamond substrate material which has a low level of intrinsic defects; processing the single crystal diamond substrate material to form a single crystal diamond substrate having a growth surface on which the CVD single crystal diamond material is to be homoepitaxially grown, wherein the growth surface of the single crystal diamond substrate has a density of defects below 5×103/mm2 as measured by optical evaluation after application of a revealing plasma etch; etching the growth surface of the single crystal diamond substrate to remove surface damage introduced during processing of the single crystal diamond substrate material; and providing a source of gas, dissociating the source gas to produce a synthesis atmosphere which contains 300 ppb to 500 ppm nitrogen, calculated as molecular nitrogen, and allowing homoepitaxial diamond growth on the growth surface of the single crystal diamond substrate to produce the single crystal CVD diamond material, wherein the single crystal CVD diamond material is coloured and has a low ramp as set out in the table below:DesignationForm of CurveAbsorption CoefficientRampRising background of formContribution at 510 nm is:Absorption coefficient <3 cm−1)(cm−1) = C × λ−3) (C = constant, λ in μm) and wherein the single crystal CVD diamond material contains one or more defect and impurity related colour centres that contribute to an absorption spectrum as set out in the absorption coefficient column of the table below:AbsorptionDesignationStarts EndsPeakcoefficient (at peak)270 nm220 nm 325 nm 270 nm0.1 cm−1 − 30 cm−1350 nm band270 nm 450 nm 350 nm +/− 0.3 cm−1 − 20 cm−110 nm510 nm band420 nm640 nm510 nm +/− 0.1 cm−1 − 10 cm−150 nm570/637 nm 500 nm 640 nm 570 nm0.1 cm−1 − 5 cm−1.