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Salvador-Porroche A, Herrer L, Sangiao S, de Teresa JM, Cea P. Low-resistivity Pd nanopatterns created by a direct electron beam irradiation process free of post-treatment steps. NANOTECHNOLOGY 2022; 33:405302. [PMID: 34983030 DOI: 10.1088/1361-6528/ac47cf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 01/04/2022] [Indexed: 05/28/2023]
Abstract
The ability to create metallic patterned nanostructures with excellent control of size, shape and spatial orientation is of utmost importance in the construction of next-generation electronic and optical devices as well as in other applications such as (bio)sensors, reactive surfaces for catalysis, etc. Moreover, development of simple, rapid and low-cost fabrication processes of metallic patterned nanostructures is a challenging issue for the incorporation of such devices in real market applications. In this contribution, a direct-write method that results in highly conducting palladium-based nanopatterned structures without the need of applying subsequent curing processes is presented. Spin-coated films of palladium acetate were irradiated with an electron beam to produce palladium nanodeposits (PdNDs) with controlled size, shape and height. The use of different electron doses was investigated and its influence on the PdNDs features determined, namely: (1) thickness of the deposits, (2) atomic percentage of palladium content, (3) oxidation state of palladium in the deposit, (4) morphology of the sample and grain size of the Pd nanocrystals and (5) resistivity. It has been probed that the use of high electron doses, 30000μC cm-2results in the lowest resistivity reported to date for PdNDs, namely 145μΩ cm, which is only one order of magnitude higher than bulk palladium. This result paves the way for development of simplified lithography processes of nanostructured deposits avoiding subsequent post-treatment steps.
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Affiliation(s)
- Alba Salvador-Porroche
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Laboratorio de Microscopías avanzadas (LMA), Universidad de Zaragoza, E-50018 Zaragoza, Spain
| | - Lucía Herrer
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Laboratorio de Microscopías avanzadas (LMA), Universidad de Zaragoza, E-50018 Zaragoza, Spain
| | - Soraya Sangiao
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Laboratorio de Microscopías avanzadas (LMA), Universidad de Zaragoza, E-50018 Zaragoza, Spain
| | - José María de Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Laboratorio de Microscopías avanzadas (LMA), Universidad de Zaragoza, E-50018 Zaragoza, Spain
| | - Pilar Cea
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain
- Laboratorio de Microscopías avanzadas (LMA), Universidad de Zaragoza, E-50018 Zaragoza, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, E-50009 Zaragoza, Spain
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Taal AJ, Lee C, Choi J, Hellenkamp B, Shepard KL. Toward implantable devices for angle-sensitive, lens-less, multifluorescent, single-photon lifetime imaging in the brain using Fabry-Perot and absorptive color filters. LIGHT, SCIENCE & APPLICATIONS 2022; 11:24. [PMID: 35075116 PMCID: PMC8786868 DOI: 10.1038/s41377-022-00708-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/29/2021] [Accepted: 01/04/2022] [Indexed: 05/17/2023]
Abstract
Implantable image sensors have the potential to revolutionize neuroscience. Due to their small form factor requirements; however, conventional filters and optics cannot be implemented. These limitations obstruct high-resolution imaging of large neural densities. Recent advances in angle-sensitive image sensors and single-photon avalanche diodes have provided a path toward ultrathin lens-less fluorescence imaging, enabling plenoptic sensing by extending sensing capabilities to include photon arrival time and incident angle, thereby providing the opportunity for separability of fluorescence point sources within the context of light-field microscopy (LFM). However, the addition of spectral sensitivity to angle-sensitive LFM reduces imager resolution because each wavelength requires a separate pixel subset. Here, we present a 1024-pixel, 50 µm thick implantable shank-based neural imager with color-filter-grating-based angle-sensitive pixels. This angular-spectral sensitive front end combines a metal-insulator-metal (MIM) Fabry-Perot color filter and diffractive optics to produce the measurement of orthogonal light-field information from two distinct colors within a single photodetector. The result is the ability to add independent color sensing to LFM while doubling the effective pixel density. The implantable imager combines angular-spectral and temporal information to demix and localize multispectral fluorescent targets. In this initial prototype, this is demonstrated with 45 μm diameter fluorescently labeled beads in scattering medium. Fluorescent lifetime imaging is exploited to further aid source separation, in addition to detecting pH through lifetime changes in fluorescent dyes. While these initial fluorescent targets are considerably brighter than fluorescently labeled neurons, further improvements will allow the application of these techniques to in-vivo multifluorescent structural and functional neural imaging.
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Affiliation(s)
- Adriaan J Taal
- Columbia University - Department of Electrical Engineering, 500W. 120th St., Mudd 1310, New York, 10027, NY, USA
| | - Changhyuk Lee
- Columbia University - Department of Electrical Engineering, 500W. 120th St., Mudd 1310, New York, 10027, NY, USA
- Korea Institute of Science and Technology - Brain Science Institute, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Jaebin Choi
- Columbia University - Department of Electrical Engineering, 500W. 120th St., Mudd 1310, New York, 10027, NY, USA
| | - Björn Hellenkamp
- Columbia University - Department of Electrical Engineering, 500W. 120th St., Mudd 1310, New York, 10027, NY, USA
| | - Kenneth L Shepard
- Columbia University - Department of Electrical Engineering, 500W. 120th St., Mudd 1310, New York, 10027, NY, USA.
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