Luminescence centres containing two, three and four hydrogen atoms in radiation-damaged silicon

摘要

Photoluminescence measurements are reported which show that the centres responsible for the X-lines, which are created by radiation damage in silicon deliberately doped with hydrogen followed by annealing at 450 deg C, contain two, three or four hydrogen atoms at equivalent or inequivalent sites. The large hydrogen-deuterium isotope shifts observed are shown to be caused primarily by linear electron-phonon coupling and the anharmonicity of local vibrational modes. There is negligible interaction between different hydrogen atoms within each centre and the isotope shifts associated with different sites in a centre can have opposite signs.