Hydrogen diffusion and densification in amorphous silicon

Self-Diffusion in Amorphous Silicon.

The present Letter reports on self-diffusion in amorphous silicon. Experiments were done on ^{29}Si/^{nat}Si heterostructures using neutron reflectometry and secondary ion mass spectrometry. The diffusivities follow the Arrhenius law in the temperature range between 550 and 700 °C with an activation energy of (4.4±0.3)  eV. In comparison with single crystalline silicon the diffusivities are tre...

Hydrogen diffusion in Zr-Pd amorphous alloys

Nuclear Magnetic Relaxation measurements of the dipolar relaxation rate due to hydrogen diffusion in Zr-Pd amorphous alloy~ have been conducted and the results interpreted in terms of the random alloy model. It is found that even though the measured activation

Hydrogen effusion from tritiated amorphous silicon

Diffusion mechanism of hydrogen in amorphous silicon: ab initio molecular dynamics simulation.

The mechanism of H migration in amorphous Si has remained an unresolved problem. The main issue is the small activation energy (1.5 eV) relative to the known strength of Si-H bonds (2-3.5 eV). We report first-principles finite-temperature simulations which demonstrate vividly that H is not released spontaneously, as proposed by most models, but awaits the arrival of a floating bond (FB). The "m...

Structural defects and hydrogen clustering in amorphous silicon

We have studied by small angle X-ray scattering the structural evolution on the atomic and nanoscale of hydrogenated amorphous silicon prepared both by ion implantation and by plasma-enhanced chemical vapor deposition and containing a similar H content. Results show that the initial structure of both samples is homogeneous on the nanoscale. Upon annealing, low-density features on the nanometer ...