Dangling bond in amorphous hydrogenated silicon: Anomalous spin relaxation

Spin relaxation of the dangling-bond defect in undoped plasma-deposited amorphous silicon has been studied using several electron-spin-resonance methods based on finite magnetic-field-modulation frequency effects. Spin-lattice relaxation (T1) processes alone do not account for the observations. Possible origins of the anomalous spin relaxation in spectral diffusion processes are discussed. Anomalous relaxation gives an additional signature of the dangling-bond defect which varies with deposition conditions. Solutions to Blochs equations for inhomogeneous spin systems at finite magnetic-field- modulation frequency are given, and a general relationship between modulation-frequency effects in conventional ESR and electron-electron double-resonance measurements is established.