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L. Huston, A. Lugstein, J. Williams, J. Bradby:
"The high pressure phase transformation behavior of silicon nanowires";
Applied Physics Letters, 113 (2018), 123103; S. 123103-1 - 123103-5.

Received 10 July 2018; accepted 4 September 2018; published online 19 September 2018)
Si nanowires of 80-150 nm and 200-250 nm diameter are pressurized up to 22 GPa using a diamond anvil cell. Raman and x-ray diffraction data were collected during both compression and decompression. Electron microscopy images reveal that the nanowires retain a nanowire-like mor-phology (after high pressure treatment). On compression, dc-Si was observed to persist at pressures up to 19 GPa compared to 􀀁11 GPa for bulk-Si. On decompression, the metallic b-Sn phase was found to be more stable for Si nanowires compared with bulk-Si when lowering the pressure and was observed as low as 6 GPa. For the smallest nanowires studied (80-150 nm), predominately a-Si was obtained on decompression, whereas for larger nanowires (200-250 nm), clear evidence for the r8/bc8-Si phase was obtained. We suggest that the small volume of the individual Si nanowires compared with bulk-Si inhibits the nucleation of the r8-Si phase on decompression. This study shows that there is a size dependence in the high pressure behavior of Si nanowires during both compression and decompression.

http://dx.doi.org/10.1063/1.5048033