Effect of sp²-Hybridized Carbon Inclusions in Diamond Films on the Sensor Performance Toward Synchrotron Radiation

We present a study of the structural features of polycrystalline a diamond film (PCDF) synthesized by the microwave plasma-enhanced chemical vapor deposition method from a hydrogen/pentane mixture and consider its photoelectric response to synchrotron radiation. Raman spectroscopy analysis of the PCDF cross-section revealed the presence of sp²-hybridized inclusions. As the distance from the PCDF growth surface increases, the amount of the non-diamond phase also increases, while its morphology changes from amorphous to crystalline graphite-like carbon. The investigation of the photoelectric response of PCDF was carried out at the “Cosmos” station using synchrotron radiation from the VEPP-4M storage ring. The PCDF detector exhibited maximum sensitivity at low bias voltage. This effect was attributed to the increased efficiency of collecting photo-induced charge carriers from the diamond to the sp²-hybridized inclusions followed by their subsequent transport through conductive paths along the boundaries between diamond crystallites.