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Low-temperature germanium thin films on silicon

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Details

Original languageEnglish
Pages (from-to)856-865
Number of pages10
JournalOptical Materials Express
Volume1
Issue number5
DOIs
Publication statusPublished - 1 Sep 2011
Publication typeA1 Journal article-refereed

Abstract

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°C, mono-crystalline between 225 and 400°C, poly-crystalline above 450°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 μm.