High-resolution radial distribution function of pure ion-implanted amorphous silicon measured using...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Amorphous silicon (a-Si) is a non-crystalline form of silicon with unique electronic and optical properties.
• Ion implantation is a key technique for modifying the structure and properties of amorphous silicon.
• Understanding the atomic structure of ion-implanted amorphous silicon is crucial for its applications.

Purpose of the Study:

• To quantitatively analyze the atomic structure of as-implanted and thermally relaxed amorphous silicon.
• To investigate the subtle atomic rearrangements occurring during low-temperature annealing in ion-implanted amorphous silicon.

Main Methods:

• High-resolution radial distribution functions were measured using tilted-illumination selected area electron diffraction.
• Diffracted intensities were collected up to a scattering vector of 3.3-3.7 Å-1 at room temperature.

Main Results:

• The pair-correlation statistics of as-implanted and relaxed amorphous silicon were found to be virtually indistinguishable.
• Coordination numbers were measured as 3.7 ± 0.3 (as-implanted) and 3.9 ± 0.3 (relaxed).
• Average bond angles were determined to be 109 ± 0.5° (as-implanted) and 110 ± 0.6° (relaxed).

Conclusions:

• Low-temperature annealing induces only subtle atomic rearrangements in ion-implanted amorphous silicon.
• The structural differences between as-implanted and thermally relaxed states are minimal.
• This suggests limited structural evolution under mild annealing conditions for this material.