An NMR investigation of H cluster configurations in a-Si:H

Conference · Tue Jul 01 04:00:00 EDT 1997

OSTI ID:20085477

Stephen, J T; Rutland, J M; Han, D; Wu, Y

In this work the characteristics of hydrogen clusters in hot filament assisted CVD and conventional glow discharge a-Si:H films are discussed. Computer simulations of the observed free-induction decays of the {sup 1}H NMR signals indicate that the distribution of the nearest-neighbor distances between H atoms in the H clusters is quite narrow in hot filament assisted CVD a-Si:H whereas the distribution is larger in glow discharge a-Si:H. This is clear evidence of improved structural order in hot filament assisted CVD a-Si:H. The relaxed hydrogenated divacancy and multi-vacancy models reproduce the main features of the observed free-induction decay in hot-wire a-Si:H very well. Computer simulations of the multiple-quantum NMR spectra indicate that a relaxed hydrogenated divacancy configuration leads to good agreement with experimental observations in device quality glow discharge a-Si:H. Results of simulations based on other H cluster configurations are also discussed. These results provide restrictions on the possible models for H clusters in a-Si:H.

• Research Organization: Univ. of North Carolina, Chapel Hill, NC (US)
• Sponsoring Organization: National Science Foundation; National Renewable Energy Laboratory
• OSTI ID: 20085477
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
ATOMIC CLUSTERS
CRYSTAL STRUCTURE
HYDROGEN ADDITIONS
NUCLEAR MAGNETIC RESONANCE
ORDER PARAMETERS
SILICON