High-Pressure High-Temperature Single-Crystal Diamond Type IIa Characterization for Particle Detectors

Various samples of multisectoral high-pressure high-temperature (HPHT) single-crystal diamond plate (IIa type) (4 x 4 x 0.53 mm) are tested for particle detection applications. The samples are investigated by X-ray diffractometry, photoluminescence spectroscopy, Raman spectroscopy, Fourier-transform infrared, and visible/ultraviolet (UV) absorption spectroscopy. High crystalline perfection and low impurity concentration (in the {100} growth sector) are observed. To investigate detector parameters, circular 1.0 and 1.5 mm diameter Pt Schottky barrier contacts are created on {111} and {100} growth sectors. On the backside, a Pt contact (3.5 x 3.5 mm) is produced. The {100} growth sector is proved to be a high-quality detector: the full width at half maximum energy resolution is 0.94% for the 5.489 MeV Ra-226 alpha-line at an operational bias of +500 V. Therefore, it is concluded that the HPHT material {100} growth sector is used for radiation detector production, whose quality is not worse than the chemical vapor deposition method or specially selected natural diamond detectors.