Growth and characterization of nc-Ge prepared by microwave annealing

Ge nanocrystals embedded in Silicon oxide matrix have been synthesized on Si substrate by co-sputtering of SiO₂ and Ge using RF magnetron sputtering technique. The as deposited films were subjected to microwave annealing at 800 and 900 °C. The structural characterization was performed by using X-ray diffraction (XRD) and Raman spectrometry. XRD measurements confirmed the formation of Ge nanocrystals. Raman scattering spectra showed a peak of Ge-Ge vibrational mode around 299 cm⁻¹, which was caused by quantum confinement of phonons in the Ge nanocrystals. Variation of the nanocrystal size with annealing temperature has been discussed. Advantages of microwave annealing are explained in detail.