Influence of annealing on structural and optical properties of Germanium quantum dots

Abstract

Ge nanodots are grown on a Si(100) substrate by radio frequency magnetron sputtering deposition technique. The role of anneali ng temperature on structural and optical properties is studied. The formation of nanodots is confirmed by X-ray diffraction pattern and the particle size is estimated to be ~ 6.5 to 8.5 nm. The structure and optical characterizations are made using, Energy dispersive X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, photoluminescence and Raman spectroscopy. The interface intermixing and the size of the nanodots are determined from Raman spectra and field emission scanning electron micrograph. Root mean square roughness and number density are found to be strongly influenced by annealing temperature. Photoluminescence spectra show s the strong emission peak at 3.21 eV accompanied by two weaker peaks at around 2.85 and 4.13 eV in the visible region. The red shift of the strong peak ~ 0.05 eV is attributed to the effect of quantum confinement.