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

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2020-06-01
Major/Subject
Mcode
Degree programme
Language
en
Pages
16
Series
ADVANCED OPTICAL MATERIALS
Abstract
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 complementary metal oxide semiconductor (CMOS) sensor manufacturing. The results imply that nanostructured Ge has potential to revolutionize the sensitivity of Ge-based sensors.
Description
| openaire: EC/H2020/777222/EU//ATTRACT
Keywords
germanium, nanostructures, dry etching, sensors, near-infrared
Other note
Citation
Pasanen , T , Isometsä , J , Garin , M , Chen , K , Vähänissi , V & Savin , H 2020 , ' Nanostructured germanium with >99% absorption at 300-1600 nm wavelengths ' , Advanced Optical Materials , vol. 8 , no. 11 , 2000047 . https://doi.org/10.1002/adom.202000047