Diatomic-hydrogen-complex dissociation: A microscopic model for metastable defect generation in Si.

Abstract

Using first-principles calculations, we demonstrate an explicit reaction pathway for carrier-induced changes in hydrogenated Si through dissociation of paired-H complexes. The complex dissociates through the capture of charge carriers with calculated kinetic barriers for electron- and hole-induced dissociations of 1.1 and 0.9 eV, respectively, in crystalline Si, in general agreement with the experimentally observed activation energies for single-carrier defect creation in hydrogenated a-Si. Exciton lowering of the barrier accounts for the low activation energy of light-induced defect formation.