Growth of endotaxial Ge nanocrystals in Si(100) matrix via low-energy ion implantation

Embedded structures in a crystalline substrate, endotaxial structures, play a major role in thermoelectric and optoelectronic applications. Here, we have fabricated Ge nanostructures inside Si(100) matrix via low-energy Ge+ ion implantation. Thermally grown SiO2 layer over the Si substrate has been used as a protective coating to avoid low-energy sputtering of the Si surface. 300 keV Ge ions are implanted into Si(100) matrix at two different fluences, 1 × 1015 and 5 × 1015 ions/cm2. After annealing the as-implanted specimens at 800 °C under the inert atmosphere for 1 h, the growth of Ge nanoclusters has been studied by Raman spectroscopy. Endotaxial nature of the Ge nanocrystals has been studied using cross-sectional high-resolution TEM. The compatibility between Ge and Si at the nanocrystal/matrix interface has been discussed in detail using high-resolution phase-contrast imaging.