Low-temperature (210 °C) deposition of crystalline germanium via in situ disproportionation of GeI2

A new approach is reported for depositing crystalline germanium films. The deposition occurs at low temperatures (210–260 °C) via in situ disproportionation of GeI2 and is thereby useful for depositing Ge onto a wide range of surfaces. Deposition onto glass and polymer substrates is demonstrated. The rate of deposition onto glass is found to be 25 ng min−1. New synthetic routes to GeI2, GeI4, and Cu3Ge are also reported. These are valuable precursors for the synthesis of germanium nanostructures and organo-germanium compounds.

Graphical abstractFormation of GeI2 from Ge and CuI at 400 °C followed by disproportionation at 210 °C deposits polycrystalline Ge. Deposition of GeI2 and GeI4 occurs in the regions below 210 °C.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Germanium deposition at temperatures as low as 210 °C. ► Deposition proceeds via in situ disproportionation of GeI2. ► Glass and polymer substrates were successfully coated. ► The deposition rate is 25 ng min−1. ► This approach utilizes simple glass apparatus.