1
|
Dutovs A, Popļausks R, Putāns O, Perkanuks V, Jurkevičiūtė A, Tamulevičius T, Malinovskis U, Olyshevets I, Erts D, Prikulis J. In situ optical sub-wavelength thickness control of porous anodic aluminum oxide. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:126-133. [PMID: 38317824 PMCID: PMC10840541 DOI: 10.3762/bjnano.15.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/11/2024] [Indexed: 02/07/2024]
Abstract
Porous anodic aluminum oxide (PAAO), sometimes referred to as nanoporous anodic alumina, serves as a cost-effective template for nanofabrication in many fields of science and engineering. However, production of ultrathin PAAO membranes with precise thickness in the optical sub-wavelength range remains challenging because of difficulties regarding process control at the initial stage of anodic oxidation. In this study, we demonstrate a technique for consistently manufacturing PAAO with the targeted thickness. An electrochemical cell with an optical window was designed for reflectance spectroscopy of PAAO during anodization. Real-time fitting of spectra to a transfer-matrix model enabled continuous monitoring of the thickness growth of the PAAO layer. Automation software was designed to terminate the anodization process at preset PAAO thickness values. While the concept was illustrated using the widely used method of anodization in a 0.3 M oxalic acid electrolyte with a 40 V potential, it can be readily customized for other protocols. PAAO layers with effective thickness below 300 nm could be produced with a few nanometers accuracy using single-crystal aluminum substrates. The results were confirmed using spectroscopic ellipsometry. The method for controlling the thickness during anodization eliminates the necessity of sample sectioning for electron microscopy and is particularly valuable for the small-scale production of PAAO-based functional optical coatings.
Collapse
Affiliation(s)
- Aleksandrs Dutovs
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Raimonds Popļausks
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Oskars Putāns
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Vladislavs Perkanuks
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Aušrinė Jurkevičiūtė
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
- Institute of Materials Science of Kaunas University of Technology, K. Baršausko St. 59, Kaunas LT-51423, Lithuania
| | - Tomas Tamulevičius
- Institute of Materials Science of Kaunas University of Technology, K. Baršausko St. 59, Kaunas LT-51423, Lithuania
- Department of Physics, Faculty of Mathematics and Natural Sciences, Kaunas University of Technology, Studentų St. 50, Kaunas LT-51368, Lithuania
| | - Uldis Malinovskis
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Iryna Olyshevets
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
| | - Donats Erts
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
- Faculty of Chemistry, University of Latvia, 1 Jelgavas Str., Riga LV-1004, Latvia
| | - Juris Prikulis
- Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia
- Faculty of Physics, Mathematics and Optometry, University of Latvia, 3 Jelgavas Str., Riga LV-1004, Latvia
| |
Collapse
|
2
|
Yager T, Chikvaidze G, Wang Q, Fu Y. Graphene Hybrid Metasurfaces for Mid-Infrared Molecular Sensors. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2113. [PMID: 37513124 PMCID: PMC10385330 DOI: 10.3390/nano13142113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023]
Abstract
We integrated graphene with asymmetric metal metasurfaces and optimised the geometry dependent photoresponse towards optoelectronic molecular sensor devices. Through careful tuning and characterisation, combining finite-difference time-domain simulations, electron-beam lithography-based nanofabrication, and micro-Fourier transform infrared spectroscopy, we achieved precise control over the mid-infrared peak response wavelengths, transmittance, and reflectance. Our methods enabled simple, reproducible and targeted mid-infrared molecular sensing over a wide range of geometrical parameters. With ultimate minimization potential down to atomic thicknesses and a diverse range of complimentary nanomaterial combinations, we anticipate a high impact potential of these technologies for environmental monitoring, threat detection, and point of care diagnostics.
Collapse
Affiliation(s)
- Tom Yager
- Institute of Solid State Physics, University of Latvia, LV-1063 Riga, Latvia
| | - George Chikvaidze
- Institute of Solid State Physics, University of Latvia, LV-1063 Riga, Latvia
| | - Qin Wang
- RISE Research Institutes of Sweden AB, Box 1070, SE-164 25 Kista, Sweden
| | - Ying Fu
- School of Information Technology, Halmstad University, SE-301 18 Halmstad, Sweden
| |
Collapse
|