Nanostructured germanium with >99% absorption at 300-1600 nm wavelengths

Research output: Contribution to journalArticleScientificpeer-review


Research units

  • Universitat de Vic – Universitat Central de Catalunya


Near-infrared (NIR) sensors find numerous applications within various industry fields, including optical communications and medical diagnostics. However, the state-of-the-art NIR sensors made of germanium (Ge) suffer from rather poor response, largely due to high reflection from the illuminated device surface. This work demonstrates a method to increase the sensitivity of Ge sensors by implementing nanostructures to the wafer surfaces. The absorbance of nanostructured Ge wafers is measured to be >99 % in the whole UV-VIS-NIR spectrum up to 1600 nm wavelength, which is a significant improvement to bare Ge wafers that reach absorption of only 63 % in maximum. The process is shown to be capable of producing uniform nanostructures covering full 100-mm-diameter substrates as well as wafers with etch mask openings of different sizes and shapes, which demonstrates its applicability to CMOS sensor manufacturing. The results imply that nanostructured Ge has potential to revolutionize the sensitivity of Ge-based sensors.


Original languageEnglish
Number of pages16
Early online date29 Mar 2020
Publication statusE-pub ahead of print - 29 Mar 2020
MoE publication typeA1 Journal article-refereed

    Research areas

  • germanium, nanostructures, dry etching, sensors, near-infrared

ID: 41495835