Characterisation of high-quality thick single-crystal diamond grown by CVD with a low nitrogen addition

Single-crystal homoepitaxial diamond has been grown by chemical vapour deposition using a high-density microwave plasma. It has been shown that the growth rate can be increased by factors of up to 2.5 by adding small concentrations (2 to 10 ppm) of nitrogen to the gas phase. Free-standing specimens up to 1.7 mm thick have been characterised using optical absorption, cathodoluminescence, photoluminescence and Raman spectroscopies, and by electron paramagnetic resonance. These techniques all demonstrate that the colourless type IIa material is of excellent quality with total defect concentrations not exceeding 200 ppb, and is ideally suited for optical and electronic applications.