Growth of embedded Ge nanocrystals on different substrates

Abstract

The formation mechanism of Ge nanocrystals embedded in a SiO2 matrix on Si(100) and quartz substrates was systemically studied with multiple techniques, including x-ray diffraction, transmission electron microscopy, and fluorescence x-ray absorption fine structure. It was found that, on the quartz substrate, the content of GeO2-like species keeps no change during the annealing process. On the contrary, on the Si(100) substrate, the segregated GeO2 from the supersaturated GeO2-SiO2 solid solution can be reduced by Si atoms diffused from the substrate to form Ge nanocrystals. However, the Ge atoms in the stable GeO2-SiO2 solid solution cannot be reduced by the Si substrate under the annealing temperature of 1073 K.