Preferential amorphisation of Ge nanocrystals in a silica matrix

Extended X-ray absorption fine structure and Raman spectroscopies have been used to compare the crystalline-to-amorphous phase transformation in nanocrystalline and polycrystalline Ge. We demonstrate Ge nanocrystals are extremely sensitive to ion irradiation and are rendered amorphous at an ion dose ∼40 times less than that required to amorphise bulk, crystalline standards. This rapid amorphisation is attributed to the higher-energy nanocrystalline structural state prior to irradiation, inhibited Frenkel pair recombination when Ge interstitials are recoiled into the matrix and preferential nucleation of the amorphous phase at the nanocrystal/matrix interface. © 2005 Elsevier B.V

Keywords

Charged particles, Crystal defects, Crystal structure, Nanocrystals, Electron microscopy, Laser spectroscopy, Raman spectroscopy, Minerals, Oxide minerals, Point defects

Citation

Ridgway, M. C., Azevedo, G. D. M., Elliman, R. G., Wesch, W., Glover, C. J., Miller, R., Llewellyn, D. J., Foran, G. J., Hansen, J. L.& Nylandsted Larsen, A. (2004). Preferential amorphisation of Ge nanocrystals in a silica matrix. Paper presented to the 14th International Conference on Ion Beam Modification of Materials, Pacific Grove, California, USA, 5-10 September 2004. In Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 242(1-2), 121-124. doi:10.1016/j.nimb.2005.08.024