On the role of the dangling bond as a radiative centre in a-Si:H

A comparison of recent ODMR results a-Si : H with previously reported ESR and LESR measurements suggests that a principal radiative electron centre has g=2.0055 and may therefore be identified as the dangling board. Our results suggest that the dangling bond (DB) can participate in two distinct PL transitions, centred near 1.25 eV and 0.9 eV, which are present to a measurable extent in all samples examined, in the medium-to-high quantum efficiency range (η_PL ～ 0.1?1.0). This conclusion is in contrast with the generally accepted role of the dangling bond in a-Si : H as primarily a non-radiative recombination centre, but is consistent with a variety of data from other experimental techniques.