OPTICALLY DETECTED MAGNETIC-RESONANCE OF SI DONORS IN ALXGA1-XAS

Magnetic resonance signals detected both on visible and on infrared luminescence bands from Si-doped AlxGa1-xAs samples are described. Most samples show two superimposed resonance signals: a four-line hyperfine pattern and a single line. In this paper we focus on the single-line spectrum, which can be attributed to the Si donor system. The results, particularly the dependence of the g values and the linewidth on the aluminum content of the samples, are explained in terms of effective-mass theory. The resonance is concluded to occur in the donor level D3, with mixed X, L, and GAMMA character in a local symmetry C2 or lower. A reduced intensity of the signal in the sigma- component of the visible luminescence in heavily doped samples is explained in terms of an anomalous relaxation mechanism.