A study, using in situ interference-enhanced Raman spectroscopy, was made of ultra-thin crystalline films which had been grown at 300C. The Raman spectra exhibited a peak at about 290/cm which was attributed to the confined optical phonon and to a broad band, on the low-frequency side, at about 254/cm for 0.5 and 1nm-thick films. The latter was attributed to a disordered surface with large numbers of dangling bonds. In thicker films, the low-frequency mode appeared at 270/cm and was attributed to surface optical phonons.

In situ Raman monitoring of ultra-thin Ge films S.Kanakaraju, A.K.Sood, S.Mohan: Journal of Applied Physics, 1998, 84[10], 5756-60