Figure 1

HRTEM images and XRD spectra of the freestanding Si NCs. (a, b) HRTEM image of the freestanding Si NCs for Si-30 and Si-40, respectively. (c) HRTEM lattice image of Si-10 NCs showing distorted lattice (regions marked with oval ring) due to the presence of compressive strain. Inset shows the SAED pattern of the Si-NCs. (d) The histogram of size distribution of NCs in Si-40. Lognormal fitting (red line) to the size distribution shows an average size of 6.8 nm. (e) The XRD spectra of the Si NCs with different durations of milling and unmilled Si powder. (f) Ungar and Borbely plot for Si-10. The linear fit to the experimental data is shown with dotted line. (g) Evolution of size and dislocation density with the milling time for Si NCs as calculated from the above plot. For comparison, sizes obtained from HRTEM images are also shown with solid circles. The error bars are too small to be seen in the graph.