Size-dependent evolution of phonon confinement in colloidal Si nanoparticles

作者：Zhang Pengfei^*; Feng Yu; Anthony Rebecca; Kortshagen Uwe; Conibeer Gavin; Huang Shujuan

来源：Journal of Raman Spectroscopy, 2015, 46(11): 1110-1116.

DOI：10.1002/jrs.4727

• phonon confinement
• Raman spectroscopy
• Si nanoparticles

A size-dependent evolution of phonon confinement is revealed in Si nanoparticles (NPs) via Raman spectroscopy. By introducing a variable confinement factor, alpha, into a well-known phenomenological phonon confinement model (PCM) developed by Richter et al., acceptable fits are achieved to downshifted and asymmetrically broadened Raman spectra of Si NPs with different diameters, d, from 2.4 nm to 6.3 nm. A comparative study using Raman spectra of colloidal Si NPs, for the first time, shows an apparent positive linear correlation between alpha and the Si NP size. Based on the PCM, the amplitude of the atomic vibration (phonon) at the real physical boundary of NPs is proportional to e(-alpha/2), which indicates that the amplitude of the first order optical phonon is relatively larger at the edges for smaller Si nanostructures despite of their stronger phonon confinement weighed by alpha/d(2).

• 出版日期2015-11