Sb. Zhang et Hm. Branz, Nonradiative electron-hole recombination by a low-barrier pathway in hydrogenated silicon semiconductors, PHYS REV L, 84(5), 2000, pp. 967-970
A microscopic pathway for nonradiative electron-hole recombination by large
structural reconfiguration in hydrogenated Si is found with first-principl
es calculations. Trapped-biexciton formation leads to a low-barrier reconfi
guration of the H atom, accompanied by crossing of doubly occupied electron
and hole levels in the band gap. This crossing represents the nonradiative
recombination of the carriers, without multiphonon emission. The proposal
provides a mechanism for carrier-induced H emission during metastable degra
dation of hydrogenated amorphous silicon.