Abstract
The electrical and optical properties of nanostructured Ge and Si are different from those of bulk materials. We investigated the properties of Ge films deposited by a cluster-beam technique mainly using Raman spectroscopy as well the techniques of AFM, TEM, XRD, PL, XPS and optical absorption. The Ge films were deposited on Si and quartz substrates at room (Ge-RT) and liquid nitrogen (Ge-LNT) temperatures. AFM images showed the presence of nanostructures in Ge-LNT and smooth surfaces in Ge-RT. Raman spectroscopy showed two modes at 266cm-1 and 271cm-1 for both films, which are different from that of a diamond structure of Ge (300cm-1). Ge-RT films showed a line at 300cm-1 by annealing the films above 700°C, while Ge-LNT did not produce such a line up to the 700°C annealing temperature. And Ge-LNT films were quickly oxided by the UV light and showed a blue PL emission at 2.9eV.
