| 1. |
- Graczyk, Mariusz, et al.
(författare)
-
Nanoimprint stamps with ultra-high resolution : Optimal fabrication techniques
- 2018
-
Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317. ; 190, s. 73-78
-
Tidskriftsartikel (refereegranskat)abstract
- Single-digit nanometer patterning by nanoimprint lithography is a challenging task, which requires optimum stamp fabrication technique. In the current work, we present different strategies for technology of hard master stamps to make intermediate working stamps with sub-10 nm features. Methods of both negative and positive master stamps fabrication, based on EBL, RIE and ALD are described and compared. A single-step copying of negative master stamps using a polymer material is a preferred strategy to reach the ultra high-resolution. Lines as small as 5.6 nm are demonstrated in a resist using a combined thermal and UV-imprint with OrmoStamp material as a working stamp.
|
|
| 2. |
- Jafari Jam, Reza, et al.
(författare)
-
III-V nanowire synthesis by use of electrodeposited gold particles
- 2015
-
Ingår i: Nano letters (Print). - Washington, DC : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 15:1, s. 134-138
-
Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires are great candidates for building novel electronic devices. Considering the cost of fabricating such devices, substrate reuse and gold consumption are the main concerns. Here we report on implementation of high throughput gold electrodeposition for selective deposition of metal seed particles in arrays defined by lithography for nanowire synthesis. By use of this method, a reduction in gold consumption by a factor of at least 300 was achieved, as compared to conventional thermal evaporation for the same pattern. Because this method also facilitates substrate reuse, a significantly reduced cost of the final device is expected. We investigate the morphology, crystallography, and optical properties of InP and GaAs nanowires grown from electrodeposited gold seed particles and compare them with the properties of nanowires grown from seed particles defined by thermal evaporation of gold. We find that nanowire synthesis, as well as the material properties of the grown nanowires are comparable and quite independent of the gold deposition technique. On the basis of these results, electrodeposition is proposed as a key technology for large-scale fabrication of nanowire-based devices.
|
|
| 3. |
- Khan, Sabbir Ahmed, et al.
(författare)
-
High-Definition Nanoimprint Stamp Fabrication by Atomic Layer Etching
- 2018
-
Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; , s. 2476-2482
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: Nanoimprint lithography (NIL) has the potential for low-cost andhigh-throughput nanoscale fabrication. However, the NIL quality and resolution areusually limited by the shape and size of the nanoimprint stamp features. Atomiclayer etching (ALE) can provide a damage-free pattern transfer with ultimate etchcontrol for features of all length scales, down to the atomic scale, and for all featuregeometries, which is required for good quality and high-resolution nanoimprintstamp fabrication. Here, we present an ALE process for nanoscale pattern transferand high-resolution nanoimprint stamp preparation. This ALE process is based onchemical adsorption of a monoatomic layer of dichloride (Cl2) on the siliconsurface, followed by the removal of a monolayer of Cl2-modified silicon by argonbombardment. The nanopatterns of different geometries, loadings, and pitcheswere fabricated by electron beam lithography on a silicon wafer, and ALE wassubsequently performed for pattern transfer using a resist as an etch mask. Thepost-ALE patterns allowed us to study the different effects and limitations of theprocess, such as trenching and sidewall tapering. The ALE-processed silicon wafers were used as hard nanoimprint stamps in a thermal nanoimprint process. Features as small as 30 nm were successfully transferred into a poly(methyl methacrylate) layer, which demonstrated the great potential of ALE in fabricating nanoimprint stamps with ultrahigh resolution.
|
|
| 4. |
- Lindberg, Frida W., et al.
(författare)
-
Design and development of nanoimprint-enabled structures for molecular motor devices
- 2019
-
Ingår i: Materials Research Express. - : IOP Publishing. - 2053-1591. ; 6:2
-
Tidskriftsartikel (refereegranskat)abstract
- Devices based on molecular motor-driven cytoskeletal filaments, e.g., actin filaments, have been developed both for biosensing and biocomputational applications. Commonly, these devices require nanoscaled tracks for guidance of the actin filaments which has limited the patterning technique to electron beam lithography. Thus, large scale systems become intractable to fabricate at a high throughput within a reasonable time-frame. We have studied the possibility to fabricate molecular motor-based devices using the high throughput, high resolution technique of nanoimprint lithography. Molecular motor-based devices require wide open regions (loading zones) to allow filaments to land for later propulsion into the nanoscale tracks. Such open zones are challenging to fabricate using nanoimprint lithography due to the large amount of material displaced in the process. We found that this challenge can be overcome by introducing nanoscaled pillars inside the loading zones, into which material can be displaced during imprint. By optimising the resist thickness, we were able to decrease the amount of material displaced without suffering from insufficient filling of the stamp. Furthermore, simulations suggest that the shape and positioning of the pillars can be used to tailor the overall cytoskeletal filament transportation direction and behaviour. This is a potentially promising design feature for future applications that however, requires further optimisations before experimental realisation.
|
|
| 5. |
- Malekian, Bita, 1986, et al.
(författare)
-
A Method for Investigation of Size-Dependent Protein Binding to Nanoholes Using Intrinsic Fluorescence of Proteins
- 2017
-
Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 2:8, s. 4772-4778
-
Tidskriftsartikel (refereegranskat)abstract
- We have developed a novel method to study the influence of surface nanotopography on human fibrinogen adsorption at a given surface chemistry. Well-ordered arrays of nanoholes with different diameters down to 45 nm and a depth of 50 nm were fabricated in silicon by electron beam lithography and reactive ion etching. The nanostructured chip was used as a model system to understand the effect of size of the nanoholes on fibrinogen adsorption. Fluorescence imaging, using the intrinsic fluorescence of proteins, was used to characterize the effect of the nanoholes on fibrinogen adsorption. Atomic force microscopy was used as a complementary technique for further characterization of the interaction. The results demonstrate that as the size of the nanoholes is reduced to 45 nm, fibrinogen adsorption is significantly increased.
|
|
| 6. |
- Otnes, Gaute, et al.
(författare)
-
Strategies to obtain pattern fidelity in nanowire growth from large-area surfaces patterned using nanoimprint lithography
- 2016
-
Ingår i: Nano Research. - : Springer Science and Business Media LLC. - 1998-0124 .- 1998-0000. ; 9:10, s. 2852-2861
-
Tidskriftsartikel (refereegranskat)abstract
- Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires. [Figure not available: see fulltext.]
|
|
| 7. |
- Pankratov, Dmitry, et al.
(författare)
-
Scalable, high performance, enzymatic cathodes based on nanoimprint lithography
- 2015
-
Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 6, s. 1377-1384
-
Tidskriftsartikel (refereegranskat)abstract
- Here we detail high performance, enzymatic electrodes for oxygen bio-electroreduction, which can be easily and reproducibly fabricated with industry-scale throughput. Planar and nanostructured electrodes were built on biocompatible, flexible polymer sheets, while nanoimprint lithography was used for electrode nanostructuring. To the best of our knowledge, this is one of the first reports concerning the usage of nanoimprint lithography for amperometric bioelectronic devices. The enzyme (Myrothecium verrucaria bilirubin oxidase) was immobilised on planar (control) and artificially nanostructured, gold electrodes by direct physical adsorption. The detailed electrochemical investigation of bioelectrodes was performed and the following parameters were obtained: open circuit voltage of approximately 0.75 V, and maximum bio-electrocatalytic current densities of 18 mu A/cm(2) and 58 mu A/cm(2) in air-saturated buffers versus 48 mu A/cm(2) and 186 mu A/cm(2) in oxygen-saturated buffers for planar and nanostructured electrodes, respectively. The half-deactivation times of planar and nanostructured biocathodes were measured to be 2 h and 14 h, respectively. The comparison of standard heterogeneous and bio-electrocatalytic rate constants showed that the improved bio-electrocatalytic performance of the nanostructured biocathodes compared to planar biodevices is due to the increased surface area of the nanostructured electrodes, whereas their improved operational stability is attributed to stabilisation of the enzyme inside nanocavities.
|
|
| 8. |
- Pankratov, Dmitry, et al.
(författare)
-
Transparent and flexible, nanostructured and mediatorless glucose/oxygen enzymatic fuel cells
- 2015
-
Ingår i: Journal of Power Sources. - : Elsevier BV. - 1873-2755 .- 0378-7753. ; 294, s. 501-506
-
Tidskriftsartikel (refereegranskat)abstract
- Here we detail transparent, flexible, nanostructured, membrane-less and mediator-free glucose/oxygen enzymatic fuel cells, which can be reproducibly fabricated with industrial scale throughput. The electrodes were built on a biocompatible flexible polymer, while nanoimprint lithography was used for their nanostructuring. The electrodes were covered with gold, their surfaces were visualised using scanning electron and atomic force microscopies, and they were also studied spectrophotometrically and electrochemically. The enzymatic fuel cells were fabricated following our previous reports on membrane-less and mediator-free biodevices in which cellobiose dehydrogenase and bilirubin oxidase were used as anodic and cathodic biocatalysts, respectively. The following average characteristics of transparent and flexible biodevices operating in glucose and chloride containing neutral buffers were registered: 0.63 V open-circuit voltage, and 0.6 mu W cm(-2) maximal power density at a cell voltage of 0.35 V. A transparent and flexible enzymatic fuel cell could still deliver at least 0.5 mu W cm(-2) after 12 h of continuous operation. Thus, such biodevices can potentially be used as self-powered biosensors or electric power sources for smart electronic contact lenses. (C) 2015 Elsevier B.V. All rights reserved.
|
|
| 9. |
|
|
| 10. |
- Suyatin, Dmitry, et al.
(författare)
-
Concept for assembling individual nanostructure-based components into complex devices
- 2015
-
Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567. ; 33:6
-
Tidskriftsartikel (refereegranskat)abstract
- Minute electronic (bio) devices will likely play an increasingly important role in everyday life and beyond, as overall device size often limits device functionality and applicability, a factor especially critical for brain implants. Recent progress in micro-and nanoelectronics has enabled the production of nanoscale electronic components; however, overall device size is often defined by technical and technological limitations, in particular, the ability to combine heterogeneous components made using incompatible processes on different substrates. Here, the authors suggest and evaluate a concept and approach aimed at the direct three-dimensional assembly of individual nanoscale-based components into complex devices for brain implants. They demonstrate this assembly possibility via the transfer of free-standing GaP nanowires, as well as test devices made of gold film which exhibit good quality electrical contacts. The key features essential for such a functional assembly process are discussed. The authors expect this approach to be generic and to enable the development of complex minute electronic (bio) devices based on nanoscale components. The proposed type of assembly may be especially beneficial for devices with strict size constraints, such as implantable neural interfaces. (C) 2015 American Vacuum Society.
|
|
