A new model was presented for the light-induced creation of 2 types of dangling bond, normal dangling and H-related, in amorphous hydrogenated material. It was found to be possible to account for the fact that the main dangling bonds were normal ones in high-quality samples, while both types of dangling bond existed in low-quality samples which contained a large amount of H.

Light-Induced Creation and Annihilation of Two Types of Dangling Bonds in a-Si:H - Their Relative Densities during Illumination K.Morigaki, H.Hikita: Solid State Communications, 2000, 114[2], 69-74