Hi Ujjwal

Nano Si typically gives Raman peaks at lower Raman shifts than bulk Si. This size-dependent shift and the associated line broadening for nanocrystalline Si relative to bulk crystalline Si is due to surface relaxation effects (i.e. Si atoms at the surface of particles will have a larger Si-Si separation and weaker bonding than Si atoms in the bulk). There are many papers which report the same phenomenon. I have listed a few below, of which I think the first one (attached) is the most useful in answering your queries.

Size-Dependent Raman Red Shifts of Semiconductor Nanocrystals

C. C. Yang* and S. Li,    J. Phys. Chem. B 2008, 112, 14193–14197

Crystal size and temperature measurements in nanostructured silicon

using Raman spectroscopy

G. Viera, S. Huet, and L. Boufendi,   JOURNAL OF APPLIED PHYSICS VOLUME 90, NUMBER 8, 2001, 4177-4183

Raman properties of silicon nanoparticles

Cedrik Meier, Stephan Luttjohann, Vasyl G. Kravets, Hermann Nienhaus,

Axel Lorke, Hartmut Wiggers, Physica E 32 (2006) 155–158

Best

Geoff

In general, broadening means more randomness. See for example (though in a different field) High Energy Density Physics, Volume 5, Issue 4, p. 225-233, especially the examples with crystals in the introduction

Thanks to both of you for sharing.