OPTICALLY DETECTED MAGNETIC-RESONANCE STUDY OF A METASTABLE SELENIUM-RELATED CENTER IN SILICON

A metastable selenium-related complex defect in silicon has recently been reported to give rise to two different deep photoluminescence (PL) spectra, originating from a bound-exciton (BE) recombination at two different configurations (referred to as A and B) of the same center. In this paper, we report on studies of this defect by optically detected magnetic resonance (ODMR). The lowest BE state, in the A configuration, is shown to be a spin-triplet state and the symmetry of the defect in this configuration is determined to be monoclinic I. In this symmetry one of the principal spin axes (y) is along the [11»0] direction, while the other two principal spin axes (z and x) lie in the (11»0) plane. The z axis is in this case is 22°away from the [111] axis towards the [001] axis, and the x axis is orthogonal to the y and z axes. The broad ODMR linewidth is attributed to an unresolved hyperfine interaction, most likely due to a copper atom in the center. This is further supported by the experimentally observed shift of the ODMR resonance positions, induced by an anticrossing of the magnetic sublevels. The conversion between the two configurations, either by above band-gap light (SeASeB) or by thermal annealing at temperatures >60 K (SeBSeA), can be followed in PL and also in ODMR. © 1995 The American Physical Society.