A hydrogen-related defect and the Staebler–Wronski effect in hydrogenated amorphous silicon

Abstract The temperature dependence of an additional 1H NMR signal that appears in a-Si:H only after light soaking is very different from the NMR signal due to bonded hydrogen and trapped molecular hydrogen. This `doublet' signal is attributed to a pair of hydrogen atoms approximately 2.3 A apart. From the temperature dependence we show that the lineshape of this site is consistent with a pair of hydrogen atoms. We also examine the spin-lattice relaxation from 6.5 to 20 K. At low temperatures, the spin-lattice relaxation time of these paired hydrogen sites has a strong dependence on temperature.