Growth of Ge islands and nanocrystals using RF magnetron sputtering and their characterization

Ge nanocrystals of different sizes and densities have been grown on p-Si(100) substrates by radio-frequency magnetron sputtering. We have also synthesized Ge nanocrystals embedded in a SiO2 matrix, using a suitable target, followed by post-deposition annealing at 900 °C in a N2 atmosphere. Atomic force and transmission electron micrographs revealed the formation of Ge clusters on the Si and within the SiO2 matrix, respectively. Infrared and x-ray photoelectron spectroscopy were used to study the chemical bonding in the deposited films. Raman spectra for Ge embedded in the SiO2 matrix show a peak at 300 cm−1 corresponding to the Ge–Ge phonon mode. A photoluminescence study has been performed at room temperature to detect the light emission from the Ge nanocrystals.