Thermal annealing effects of dangling bonds in hydrogenated polymorphous silicon

We investigate the effect of thermal annealing on the density of thermally induced native dangling bonds existing in the amorphous network and created during sample preparation in hydrogenated polymorphous silicon (pm-Si:H) by means of electron spin resonance (ESR). The decay curve of the ESR signal intensity associated with dangling bonds is fitted by a stretched exponential function. The dispersion parameter Β and the characteristic time τ are deduced and compared to those for hydrogenated amorphous silicon (a-Si:H). The results are discussed in terms of rapid hydrogen motion associated with the peculiar structure of pm-Si:H.