Projects per year
Abstract
Nanostructured surfaces are known to provide excellent optical properties for various photonics devices. Fabrication of such nanoscale structures to germanium (Ge) surfaces by metal assisted chemical etching (MACE) is, however, challenging as Ge surface is highly reactive resulting often in micron-level rather than nanoscale structures. Here we show that by properly controlling the process, it is possible to confine the chemical reaction only to the vicinity of the metal nanoparticles and obtain nanostructures also in Ge. Furthermore, it is shown that controlling the density of the nanoparticles, concentration of oxidizing and dissolving agents as well as the etching time plays a crucial role in successful nanostructure formation. We also discuss the impact of high mobility of charge carriers on the chemical reactions taking place on Ge surfaces. As a result we propose a simple one-step MACE process that results in nanoscale structures with less than 10% surface reflectance in the wavelength region between 400 and 1600 nm. The method consumes only a small amount of Ge and is thus industrially viable and also applicable to thin Ge layers.
Original language | English |
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Article number | 035301 |
Number of pages | 7 |
Journal | Nanotechnology |
Volume | 32 |
Issue number | 3 |
DOIs | |
Publication status | Published - 15 Jan 2021 |
MoE publication type | A1 Journal article-refereed |
Keywords
- nanostructures
- nanoparticles
- germanium
- metal assisted chemical etching
- photonics
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Photonics Research and Innovation
Savin, H., Rauha, I., Ayedh, H. & Mulbagal Rajanna, P.
01/01/2019 → 31/12/2022
Project: Academy of Finland: Other research funding
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ATTRACT SUGER
Savin, H., Isometsä, J. & Pasanen, T.
01/05/2019 → 31/10/2020
Project: EU: Framework programmes funding