RAMAN-SPECTROSCOPY OF GERMANIUM FILMS DEPOSITED WITH CLUSTER-BEAM TECHNIQUE

The structure and the vibrational properties of germanium films deposi ted by the cluster-beam technique were investigated mainly using Raman spectroscopy. Germanium films were deposited on Si substrates at room temperature (Ge-RT) and liquid N-2 temperature (Ge-LNT). Raman as wel l as other techniques (XRD, TEM, optical absorption and PL) were used to characterize these films. The nanostructures were observed in Ge-LN T by TEM micrograph, while flat continuous images were found in Ge-RT. Raman spectra of both Ge films showed a broad peak around 270 cm(-1) different from that of cubic Ge (300 cm(-1)). Ge-RT films showed a lin e at 300 cm(-1) by annealing the films above 700 degrees C, while Ge-L NT did not give such line up to the 800 degrees C annealing. The relat ion between these spectra and the observed nanostructure is discussed.