Transient Light-Induced ESR Investigations of the Role of Hydrogen in the Stability of a-Si:H

Transient light-induced electron spin resonance (LESR) at 120 K has been used to investigate the light-soaking behaviors and the role of hydrogen in the stability of a-Si:H through changes in the lineshape. Dramatic changes occur in the LESR lineshape upon prolonged light-soaking, and we suggest that hydrogen defects (Si-H2 or clustered Si-H bonds) play an important role in these changes. A microscopic explanation of the possible optical excitations and defect conversion processes leading to these changes during the LESR experiment is proposed.