Radiation damage in dielectric and semiconductor single crystals (direct observation)

The surfaces of boron-doped synthetic and natural diamonds have been investigated by using the scanning tunnelling microscope (STM) and the scanning electronic microscope (SEM) before and after irradiating the samples with ⁴⁰Ar (25 MeV), ⁸⁴Kr (210 MeV) and ¹²⁵Xe (124 MeV) ions. The structures observed after irradiation showed craters with diameters ranging from 3 nm up to 20 nm, which could be interpreted as single ion tracks and multiple hits of ions at the nearest positions of the surface. In the case of argon ion irradiation, the surface was found to be completely amorphous, but after xenon irradiation one could see parts of surface without amorphism. This can be explained by the influence of high inelastic energy losses. The energy and temperature criteria of crater formation as a result of heavy ion irradiation are introduced.