A study of the molecular behavior in the vibronic and excitonic properties of silicon nanoparticles

The molecular behavior of silicon nanoparticles, produced via electrochemical etching of a bulk precursor, is studied. The smallest particle, 1 nrn in diameter, is amenable to first principles modeling due to the manageable number of atoms in the structure. The ability to produce these particles in macroscopic amounts allows for the testing of these models through various optical techniques. Raman spectroscopy measurements, performed on 1 nrn silicon nanoparticles suspended in liquid, were found to agree well with vibrational modes calculated using Hartree-Fock theory through the GAMESS package. The Raman peaks offer direct evidence of stretched Si-Si surface dimers in the reconstructed particle, which have been suggested to be the source of its optical activity. The peak positions and FWHM's, along with calculations of the normal modes, suggest that the nanoparticle exhibits strong molecular behavior despite its derivation from a bulk structure. Low temperature PL measurements show the involvement of the dimers in the luminescence characteristics.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Rao, Satish Kodali

Contributors dc:contributor

• Nayfeh, Munir H.

• silicon nanoparticles
• electrochemical etching
• Raman Spectroscopy
• General Atomic Molecular Electronic Structure System (GAMESS) Copmutation

Statement dc:rights

• ©2006 Rao

Language dc:language

en

Identifier

5513593

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/31394