Evaluation of quantum confinement effect in nanocrystal Si dot layer by Raman spectroscopy

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Nanocrystal-silicon (nc-Si) exhibits unique quantum properties due to its small size.
• Understanding quantum confinement is crucial for developing advanced silicon-based nanomaterials.
• Raman spectroscopy is a powerful tool for probing vibrational properties and structural changes in nanomaterials.

Purpose of the Study:

• To investigate the quantum confinement effect in nanocrystal-silicon (nc-Si) dot layers.
• To analyze the impact of post-oxidation annealing on the crystalline quality and stress in nc-Si.
• To correlate spectral changes with physical phenomena in nc-Si.

Main Methods:

• Fabrication of nc-Si dot layers using H2 plasma treatment and SiH4 irradiation.
• Evaluation of quantum confinement using Raman spectroscopy.
• Analysis of Raman spectra for asymmetric broadening and peak shifts.
• Induction and measurement of hydrostatic stress in nc-Si.

Main Results:

• Asymmetric broadening on the lower frequency side of Raman spectra observed after annealing.
• Broadening attributed to the phonon confinement effect in nc-Si.
• Hydrostatic stress of approximately 500 MPa induced in nc-Si after post-oxidation annealing.

Conclusions:

• Post-oxidation annealing enhances crystalline quality and induces significant hydrostatic stress in nc-Si.
• Raman spectral changes confirm the presence of quantum confinement effects in nc-Si.
• The study provides insights into the physical properties of nc-Si relevant for nanoelectronic applications.