The Effect of Co-Dopants on the Photoluminescence of Er 3+ in Silicon

This paper presents the results of our investigation into the possibility of increasing both the radiative cross-section and the electrical activation efficiency in erbium (Er 3+ ) doped silicon (Si). The energy levels of the isolated Er 3+ have been theoretically predicted, employing the Thomas-Fermi method. The behaviour of these levels in Si was then investigated using a Kronig-Penney approach. Initial theoretical results imply that fluorine (F), in addition to Er 3+ in Si, increases the radiative cross-section of Er 3+ by at least an order of magnitude, and that co-doping appears to enhance the mixing of the 4f and 5d levels and causes the Er 3+ energy levels to overlap with those of the host. Photoluminescence spectra of Er 3+ in Si co-doped with F also indicate an interaction with the host lattice which appears to be dependent on its electrical characteristics.