Paramagnetic states in doped amorphous silicon and germanium

ESR-results for doped hydrogenated amorphous silicon and germanium are discussed. g-values and linewidths of the resonances as well as effective correlation energies of the corresponding energy states are compared for both materials. It is shown that the existing large differences of these quantities between a-Si : H and a-Ge : H can be explained by the differences of spin-orbit coupling and degree of localization.