Sputter-deposited thin films were studied by using electron paramagnetic resonance, capacitance-voltage, optical bleaching and absorption spectroscopic techniques. It was found that there was a good qualitative agreement between the density of isolated Ge dangling bonds as measured magnetically, the density of charge-trapping sites as measured electrically, and the density of absorbing centers as measured optically. Taken all together, the observations could be modelled by assuming that there was a change in the spin state and charge state, of isolated paramagnetic neutral Ge dangling bonds, to form positively or negatively charged diamagnetic Ge sites.

W.L.Warren, K.Simmons-Potter, B.G.Potter, J.A.Ruffner: Applied Physics Letters, 1996, 69[10], 1453-5