Pulsed ESR Study of the Conduction Electron Spin Center in μc-Si:H

The spin-lattice relaxation times (T1) of conduction electron (CE) and dangling bond (DB) centers in μc-Si:H have been directly measured using the 3-pulse inversion recovery method. For both CE and DB, the inversion recovery curve follows a stretched exponential form. T1 of DB is about twice the T1 of CE, however the temperature dependence of T1 seems to be the same for both CE and DB and can be approximated by T−4 While the DB echo decay is modulated by both 29Si and 1H nuclei, we found no modulation of the CE echo decay by the H nucleus, indicating that CE centers are located in H-depleted phases in μc-Si:H. The modulation results are direct evidence that CE centers are located in the crystalline grains and DB centers in the amorphous phases.