Chemical trends for deep levels associated with vacancy-impurity complexes in semiconductors

A theory of the deep levels produced by triplet vacancy-impurity complexes in covalent semiconductors is presented. The major chemical trends in the deep levels of a₁ and b₁ symmetry are predicted for such complexes in 10 materials. These calculations show that a triplet vacancy-impurity complex can produce deep levels at energies where neither the corresponding vacancy-impurity pair nor the isolated impurity produce any.