| 51. |
- 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.
|
|
| 52. |
- Maximov, Ivan
(författare)
-
Fabrication of Low-Dimensional Structures in III-V Semiconductors
- 1997
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis presents studies on the processing technology and the characterization of nanometer-sized and low-dimensional structures in III-V semiconductors. Two major approaches are described: 1) the combination of aerosol technology and plasma etching for the fabrication of quantum dots (QDs) in InP-based materials and 2) the use of high-resolution electron beam lithography and plasma or wet chemical etching to make quantum well wires (QWWs) in both GaAs and InP-based structures. The first approach is based on parallel processing technology for the formation of arrays of QDs in an InP/GaInAs quantum well structures using aerosol-deposited masks and low-energy plasma etching. The deposition of Ag aerosol particles, 20 to 80 nm in size, with an extremely narrow size distribution, allows the formation of etch masks with densities up to 10E9 cm-2. These masks are stable under electron cyclotron resonance (ECR) plasma conditions in a CH4/H2/Ar discharge and allow the formation of arrays of QDs, 25-100 nm in size, with densities of about 10E9 cm-2. The QDs produced were investigated using scanning electron microscopy, photo- and cathodoluminescence and other methods. The second approach is more "traditional", in the sense that the processing of an individual structure is utilized. To define QWWs or QDs, high-resolution electron beam lithography and a subsequent pattern transfer by plasma or wet etching was used. QWWs in InP/GaInAs and GaAs/GaInAs material were produced by ECR plasma and wet etching for spectroscopy studies. A single 50 to 90 nm wide QWW (quantum point contact-QPC) was fabricated in a modulation-doped InP/GaInAs, lattice-mismatched structure. The epitaxially regrown QPC demonstrated a quantized conductance at temperatures of 10K and above, which indicated that the fabricated structure was of high quality. Studies of damage induced in GaAs/AlGaAs and GaAs/GaInP heterostructures by an ECR plasma have also been performed. The damage was characterized by photoluminescence, transport measurements and electron paramagnetic resonance. Experiments showed no correlation between the density of plasma-induced defects and transport or photoluminescence properties, nor between photoluminescence and transport properties.
|
|
| 53. |
- Maximov, Ivan, et al.
(författare)
-
Fabrication of Si-based nanoimprint stamps with sub-20 nm features
- 2002
-
Ingår i: MICROELECTRONIC ENGINEERING. - 1873-5568 .- 0167-9317. ; 61-2, s. 449-454
-
Konferensbidrag (refereegranskat)abstract
- We present two alternative methods for fabrication of nanoimprint lithography stamps in SiO2 with sub-20 nm features: (a) optimized electron beam lithography (EBL) and lift-off patterning of a 15-nm thick Cr mask, and (b) aerosol deposition of W particles in the 20-nm size range. In both cases, the pattern transfer into SiO2 was performed using reactive ion etching (RIE) with CHF3 as etch gas. In the first approach, we used a double layer resist system (PMMA/ZEP 520A7 positive resists) for the EBL exposure. Resist thickness, exposure dose and development time were optimized to obtain 15-20 nm features after Cr lift-off. In the second approach, we used size selected W aerosol particles as etch masks during etching of SiO2. Both methods of stamp fabrication are compared and discussed. (C) 2002 Published by Elsevier Science B.V.
|
|
| 54. |
|
|
| 55. |
- Maximov, Ivan, et al.
(författare)
-
Investigation of polymethylmethacrylate resist residues using photoelectron microscopy
- 2002
-
Ingår i: Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures. - : American Vacuum Society. - 1071-1023 .- 1520-8567 .- 0734-211X. ; 20:3, s. 1139-1142
-
Konferensbidrag (refereegranskat)abstract
- Quantitative photoelectron spectromicroscopy has been used to study polymethylmethacrylate (PMMA) resist residues on SiO2 surfaces after electron beam exposure and resist development, It was found that correctly exposed and developed PMMA leaves residues with an average thickness of about 1 nm. Higher exposure doses result in the decrease in film thickness, but with residues of about 0.5 mn. The technique can be applied as a powerful tool for surface and interface quality control in technology of electronic devices.
|
|
| 56. |
- Maximov, Ivan, et al.
(författare)
-
New high resolution negative resist mr-L 6000.1 XP for electron beam and nanoimprint lithography
- 2002
-
Ingår i: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
-
Konferensbidrag (refereegranskat)abstract
- We present the characterization results of a new high resolution negative electron beam resist mr-L 6000.1 XP. The resist can also be used as imprintable polymer in nanoimprint lithography with sub-100 nm resolution. The feature size achieved after e-beam exposure was about 50 nm with sensitivity of 2-4 μC/cm2. Studies of the resist properties as a function of chemical composition and development conditions are also presented
|
|
| 57. |
- Meng, Fantao, et al.
(författare)
-
Efficient methods of nanoimprint stamp cleaning based on imprint self-cleaning effect.
- 2011
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 22:18
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoimprint lithography (NIL) is a nonconventional lithographic technique that promises low-cost, high-throughput patterning of structures with sub-10 nm resolution. Contamination of nanoimprint stamps is one of the key obstacles to industrialize the NIL technology. Here, we report two efficient approaches for removal of typical contamination of particles and residual resist from stamps: thermal and ultraviolet (UV) imprinting cleaning-both based on the self-cleaning effect of imprinting process. The contaminated stamps were imprinted onto polymer substrates and after demolding, they were treated with an organic solvent. The images of the stamp before and after the cleaning processes show that the two cleaning approaches can effectively remove contamination from stamps without destroying the stamp structures. The contact angles of the stamp before and after the cleaning processes indicate that the cleaning methods do not significantly degrade the anti-sticking layer. The cleaning processes reported in this work could also be used for substrate cleaning.
|
|
| 58. |
- Meng, Fantao, et al.
(författare)
-
Fabrication and characterization of bilayer metal wire-grid polarizer using nanoimprint lithography on flexible plastic substrate
- 2011
-
Ingår i: Microelectronic Engineering. - : Elsevier BV. - 1873-5568 .- 0167-9317. ; 88:10, s. 3108-3112
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, we demonstrate the fabrication of bilayer metal wire-grid polarizers and the characterization of their performance. The polarizers with 200 nm period were fabricated on flexible plastic substrates by nanoimprint lithography (NIL), followed by aluminum deposition. Transmission efficiency over 0.51 and extinction ratio higher than 950 can be achieved in the visible range when the aluminum thickness of the polarizer is 100 nm. The fabrication process only involves direct imprinting on flexible plastic substrates and aluminum deposition, without any resist spin-coating, lift-off, and etching processes, which is much simpler, less costly, and applicable to large volume production. (C) 2011 Elsevier B.V. All rights reserved.
|
|
| 59. |
- Meng, Fantao, et al.
(författare)
-
Nonlinear electrical properties of Si three-terminal junction devices
- 2010
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 97:24
-
Tidskriftsartikel (refereegranskat)abstract
- This letter reports on the realization and characterization of silicon three-terminal junction devices made in a silicon-on-insulator wafer. Room temperature electrical measurements show that the fabricated devices exhibit pronounced nonlinear electrical properties inherent to ballistic electron transport in a three-terminal ballistic junction (TBJ) device. The results show that room temperature functional TBJ devices can be realized in a semiconductor material other than high-mobility III-V semiconductor heterostructures and provide a simple design principle for compact silicon devices in nanoelectronics. (C) 2010 American Institute of Physics. [doi:10.1063/1.3526725]
|
|
| 60. |
- Moltu, Sissel J., et al.
(författare)
-
Arachidonic and docosahexaenoic acid supplementation and brain maturation in preterm infants : a double blind RCT
- 2024
-
Ingår i: Clinical Nutrition. - : Elsevier. - 0261-5614 .- 1532-1983. ; 43:1, s. 176-186
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are important structural components of neural cellular membranes and possess anti-inflammatory properties. Very preterm infants are deprived of the enhanced placental supply of these fatty acids, but the benefit of postnatal supplementation on brain development is uncertain. The aim of this study was to test the hypothesis that early enteral supplementation with ARA and DHA in preterm infants improves white matter (WM) microstructure assessed by diffusion-weighted MRI at term equivalent age.Methods: In this double-blind, randomized controlled trial, infants born before 29 weeks gestational age were allocated to either 100 mg/kg ARA and 50 mg/kg DHA (ARA:DHA group) or medium chain triglycerides (control). Supplements were started on the second day of life and provided until 36 weeks postmenstrual age. The primary outcome was brain maturation assessed by diffusion tensor imaging (DTI) using Tract-Based Spatial Statistics (TBSS) analysis.Results: We included 120 infants (60 per group) in the trial; mean (range) gestational age was 26+3 (22+6 - 28+6) weeks and postmenstrual age at scan was 41+3 (39+1 - 47+0) weeks. Ninety-two infants underwent MRI imaging, and of these, 90 had successful T1/T2 weighted MR images and 74 had DTI data of acceptable quality. TBSS did not show significant differences in mean or axial diffusivity between the groups, but demonstrated significantly higher fractional anisotropy in several large WM tracts in the ARA:DHA group, including corpus callosum, the anterior and posterior limb of the internal capsula, inferior occipitofrontal fasciculus, uncinate fasciculus, and the inferior longitudinal fasciculus. Radial diffusivity was also significantly lower in several of the same WM tracts in the ARA:DHA group.Conclusion: This study suggests that supplementation with ARA and DHA at doses matching estimated fetal accretion rates improves WM maturation compared to control treatment, but further studies are needed to ascertain any functional benefit.Clinical trial registration: www.clinicaltrials.gov; ID:NCT03555019.
|
|
