"We discuss thermal evaporation of Germanium thin films as a suitable route to realizing near-infrared detectors integrated on a Silicon platform. We study the structural properties of samples grown at various substrate temperatures by X-ray diffraction and transmission electron microscopy, showing that Ge thin films are amorphous when deposited below 225 degrees C, mono-crystalline between 225 and 400 degrees C, poly-crystalline above 450 degrees C. We further investigate their optical and electrical properties using differential optical absorption spectroscopy, Hall and photocurrent measurements. Finally, with the evaporated Ge thin films we demonstrate near-infrared photodiodes with low dark current density and good responsivity at 1.55 mu m. (C) 2011 Optical Society of America"
Sorianello, V., Colace, L., Armani, N., Rossi, F., Ferrari, C., Lazzarini, L., et al. (2011). Low-temperature germanium thin films on silicon. OPTICAL MATERIALS EXPRESS, 1(5), 856-865.