R. Lewén, Ivan Maximov, Ivan Shorubalko, Lars Samuelson, L. Thylén, H. Q. Xu,
We report comprehensive microwave measurements on a T-branch switch; a GaInAs/InP electron waveguide based structure. The study includes a small signal model of the device where limitations of high frequency operation are discussed. An example of large signal operation where the nonlinearity of the device is exploited by operating the T-branch switch as a frequency multiplier is demonstrated.
Tópico(s): Radio Frequency Integrated Circuit Design
2002 - American Institute of Physics | Journal of Applied Physics
Max Korbmacher, Dennis van der Meer, Dani Beck, Ann‐Marie G. de Lange, Eli Eikefjord, Arvid Lundervold, Ole A. Andreassen, Lars T. Westlye, Ivan I. Maximov,
Abstract The human brain demonstrates structural and functional asymmetries which have implications for ageing and mental and neurological disease development. We used a set of magnetic resonance imaging (MRI) metrics derived from structural and diffusion MRI data in N =48,040 UK Biobank participants to evaluate age-related differences in brain asymmetry. Most regional grey and white matter metrics presented asymmetry, which were higher later in life. Informed by these results, we conducted hemispheric ...
Tópico(s): Morphological variations and asymmetry
2024 - Nature Portfolio | Nature Communications
Maarten G. Poirot, Henricus G. Ruhé, Henk J. M. M. Mutsaerts, Ivan I. Maximov, Inge Rasmus Groote, Atle Bjørnerud, Henk A. Marquering, Liesbeth Reneman, Matthan W.A. Caan,
Response to antidepressant treatment in major depressive disorder varies substantially between individuals, which lengthens the process of finding effective treatment. The authors sought to determine whether a multimodal machine learning approach could predict early sertraline response in patients with major depressive disorder. They assessed the predictive contribution of MR neuroimaging and clinical assessments at baseline and after 1 week of treatment.
Tópico(s): Advanced Neuroimaging Techniques and Applications
2024 - American Psychiatric Association | American Journal of Psychiatry
Sissel J. Moltu, Tone Nordvik, Madelaine Eloranta Rossholt, Kristina Wendel, Maninder Singh Chawla, Andrés Server, Gunnthorunn Gunnarsdottir, Are Hugo Pripp, Magnus Domellöf, Marianne Bratlie, Marlen Aas, Petra S. Hüppi, Alexandre Lapillonne, Mona K. Beyer, Tom Stiris, Ivan I. Maximov, Oliver Geier, Helle Cecilie Viekilde Pfeiffer,
Background &Aim: 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 ...
Tópico(s): Infant Development and Preterm Care
2023 - Elsevier BV | Clinical Nutrition
A. V. Maximov, Ivan Ourdev, D. Pesme, W. Rozmus, V. T. Tikhonchuk, C. E. Capjack,
The angular divergence and spectral bandwidth of a spatially incoherent laser beam propagating in an underdense plasma are shown to correspond to additional spatial and temporal incoherence in the regime where the average laser intensity in a speckle approaches the self-focusing threshold. The transverse and longitudinal sizes of laser speckles inside the plasma are related in a way that makes it possible to define a local effective beam f-number. The effective f-number decreases as light propagates ...
Tópico(s): Advanced Fiber Laser Technologies
2001 - American Institute of Physics | Physics of Plasmas
C. Labaune, H. A. Baldis, E. Schifano, B. S. Bauer, A. V. Maximov, Ivan Ourdev, W. Rozmus, D. Pesme,
The nonlinear enhancement of large-angle forward scattering of two identical laser beams propagating in a preformed plasma has been observed experimentally. The spectral analysis of the forward-scattered light shows two components, one which is unshifted with respect to the initial laser light frequency, and the other which is redshifted by a few angstroms. The redshifted component is found to be strongly enhanced in the case of crossed beam interaction in comparison with that of one beam illumination. ...
Tópico(s): Laser-induced spectroscopy and plasma
2000 - American Physical Society | Physical Review Letters
D. Pesme, W. Rozmus, V. T. Tikhonchuk, A. Maximov, Ivan Ourdev, C. H. Still,
The stability of nonlinear laser light filaments in a homogeneous isothermal plasma with respect to coupled electromagnetic and density perturbations is examined. In addition to the previously known modulational instability of a trapped electromagnetic mode, a new fast growing resonant instability is found. It corresponds to the growth of an excited eigenmode in the waveguide formed by the filament density depletion, the associated density response being supersonic and transversally localized. The ...
Tópico(s): Advanced Fiber Laser Technologies
2000 - American Physical Society | Physical Review Letters
B. Maximov, Ivan Petrov, A. Rabenau, H. Schulz,
X-ray investigations on single crystals of the series of rare-earth compounds Na5RESi4O12 with RE as Sc or Y were carried out at room temperature and 300°C. They show a dependence of the inner symmetry of the main conductive channels on the type of the RE ion. A simple analysis of the conductivity mechanism is presented.
Tópico(s): Glass properties and applications
1982 - Elsevier BV | Solid State Ionics
Max Korbmacher, Tiril P. Gurholt, Ann‐Marie G. de Lange, Dennis van der Meer, Dani Beck, Eli Eikefjord, Arvid Lundervold, Ole A. Andreassen, Lars T. Westlye, Ivan I. Maximov,
Brain age refers to age predicted by brain features. Brain age has previously been associated with various health and disease outcomes and suggested as a potential biomarker of general health. Few previous studies have systematically assessed brain age variability derived from single and multi-shell diffusion magnetic resonance imaging data. Here, we present multivariate models of brain age derived from various diffusion approaches and how they relate to bio-psycho-social variables within the domains ...
Tópico(s): MRI in cancer diagnosis
2023 - Frontiers Media | Frontiers in Psychology
Qin Wang, Noel A. Clark, Ivan Maximov, P. Omling, Lars Samuelson, W. Seifert, Wei-Dong Sheng, Ivan Shorubalko, H. Q. Xu,
We have measured at low temperatures the conductance of electron waveguides fabricated from modulation-doped quantum wells by wet etching and regrowth. We have found that, for a waveguide with abruptly changed geometry at the entrance and exit, the conductance shows oscillations, which are superimposed on a conventional conductance plateau structure. The periods and amplitudes of conductance oscillations depend on the length to width aspect ratio of the waveguide. In addition, the amplitudes of ...
Tópico(s): Semiconductor Quantum Structures and Devices
2000 - American Institute of Physics | Applied Physics Letters
Gaute Otnes, Magnus Heurlin, Mariusz Graczyk, Jesper Wallentin, Daniel Jacobsson, Alexander Berg, Ivan Maximov, Magnus T. Borgström,
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 ...
Tópico(s): Semiconductor materials and interfaces
2016 - Springer Science+Business Media | Nano Research
Dmitry Pankratov, Richard Sundberg, Javier Sotres, Ivan Maximov, Mariusz Graczyk, Dmitry Suyatin, Elena González‐Arribas, А. В. Липкин, Lars Montelius, Sergey Shleev,
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 ...
Tópico(s): Electrochemical Analysis and Applications
2015 - Elsevier BV | Journal of Power Sources
Dmitry Pankratov, Richard Sundberg, Dmitry Suyatin, Javier Sotres, Alejandro Barrantes, Tautgirdas Ruzgas, Ivan Maximov, Lars Montelius, Sergey Shleev,
Detailed experimental evidences that neither an overpotential of bioelectrocatalysis, nor direct electron transfer and bioelectrocatalytic reaction rates for an adsorbed enzyme depend on the size of gold nanoparticles, are presented.
Tópico(s): Advanced biosensing and bioanalysis techniques
2014 - Royal Society of Chemistry | RSC Advances
Reza Jafari Jam, Magnus Heurlin, Vishal Jain, Anders Kvennefors, Mariusz Graczyk, Ivan Maximov, Magnus T. Borgström, Håkan Pettersson, Lars Samuelson,
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 ...
Tópico(s): Chalcogenide Semiconductor Thin Films
2014 - American Chemical Society | Nano Letters
Dmitry Suyatin, Vishal Jain, В. А. Небольсин, Johanna Trägårdh, Maria E. Messing, Jakob B. Wagner, Olof Persson, Rainer Timm, Anders Mikkelsen, Ivan Maximov, Lars Samuelson, Håkan Pettersson,
Nanoscale contacts between metals and semiconductors are critical for further downscaling of electronic and optoelectronic devices. However, realizing nanocontacts poses significant challenges since conventional approaches to achieve ohmic contacts through Schottky barrier suppression are often inadequate. Here we report the realization and characterization of low n-type Schottky barriers (~0.35 eV) formed at epitaxial contacts between Au-In alloy catalytic particles and GaAs-nanowires. In comparison ...
Tópico(s): Nanowire Synthesis and Applications
2014 - Nature Portfolio | Nature Communications
Viktor Schroeder, Till Korten, Heiner Linke, Stefan Diez, Ivan Maximov,
Biomolecular motor systems are attractive for future nanotechnological devices because they can replace nanofluidics by directed transport. However, the lack of methods to externally control motor-driven transport along complex paths limits their range of applications. Based on a thermo-responsive polymer, we developed a novel technique to guide microtubules propelled by kinesin-1 motors on a planar surface. Using electrically heated gold microstructures, the polymers were locally collapsed, creating ...
Tópico(s): Advanced Materials and Mechanics
2013 - American Chemical Society | Nano Letters
Maher Harb, Clemens von Korff Schmising, H. Enquist, A. Jurgilaitis, Ivan Maximov, Petr Shvets, A. N. Obraztsov, Dmitry Khakhulin, Michaël Wulff, Jörgen Larsson,
We report on the use of time resolved X-ray diffraction to measure the dynamics of strain in laser-excited graphite film of nanometer thickness, obtained by chemical vapour deposition (CVD). Heat transport in the CVD film is simulated with a 1-dimensional heat diffusion model. We find the experimental data to be consistent with a c-axis thermal conductivity of ∼0.7 W m−1 K−1. This value is four orders of magnitude lower than the thermal conductivity in-plane, confirming recent theoretical calculations ...
Tópico(s): Silicon Carbide Semiconductor Technologies
2012 - American Institute of Physics | Applied Physics Letters
Fantao Meng, Gang Luo, Ivan Maximov, Lars Montelius, Jinkui Chu, H. Q. Xu,
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 ...
Tópico(s): Optical Coatings and Gratings
2011 - Elsevier BV | Microelectronic Engineering
Jie Sun, Erik Lind, Ivan Maximov, H. Q. Xu,
This letter reports on room-temperature electrical measurements of a Au/Ti- HfO 2 -InP/InGaAs diode fabricated by atomic layer deposition and electron beam lithography. At forward bias voltages, the diode shows memristor characteristics, whereas at reverse bias voltages, the diode can be characterized as a memcapacitor. A parasitic accumulation layer of charges formed at the high- κ oxide/InP interface is shown to be the cause for the phenomena. The operation of the diode as a rewritable memory cell ...
Tópico(s): Semiconductor materials and devices
2010 - Institute of Electrical and Electronics Engineers | IEEE Electron Device Letters
Fantao Meng, Jie Sun, Mariusz Graczyk, Kailiang Zhang, Mika Prunnila, Jouni Ahopelto, Peixiong Shi, Jinkui Chu, Ivan Maximov, H. Q. Xu,
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 ...
Tópico(s): Semiconductor materials and devices
2010 - American Institute of Physics | Applied Physics Letters
Jie Sun, Marcus Larsson, Ivan Maximov, H. Hardtdegen, H. Q. Xu,
Gate-defined quantum dots in an InGaAs/InP heterostructure are realized by incorporating a high-κ HfO2 material as a gate dielectric using atomic layer deposition. The fabricated quantum-dot devices show Coulomb blockade effect at low temperature. The Coulomb blockade current peaks are found to shift in pairs with the magnetic field applied perpendicular to the quantum-dot plane, due to the filling of electrons into spin-degenerate orbital states. When the magnetic field is applied parallel to the ...
Tópico(s): Advancements in Semiconductor Devices and Circuit Design
2009 - American Institute of Physics | Applied Physics Letters
Jie Sun, Daniel Wallin, Ivan Maximov, H. Q. Xu,
In this letter, a novel sequential logic device based on three-terminal ballistic junctions (TBJs) is proposed and demonstrated. Two TBJs and two in-plane gates are laterally integrated in a high-electron-mobility InGaAs/InP quantum-well material by a single-step lithography process. Electrical measurements reveal that the integrated device functions as a set-reset (SR) latch with voltage gains at room temperature. The demonstrated device provides a new and simple circuit design for SR latches in ...
Tópico(s): Semiconductor materials and devices
2008 - Institute of Electrical and Electronics Engineers | IEEE Electron Device Letters
Dmitry Suyatin, Jie Sun, Andreas Fuhrer, Daniel Wallin, Linus Fröberg, Lisa Karlsson, Ivan Maximov, Reine Wallenberg, Lars Samuelson, H. Q. Xu,
We investigate electrical properties of self-assembled branched InAs nanowires. The branched nanowires are catalytically grown using chemical beam epitaxy, and three-terminal nanoelectronic devices are fabricated from the branched nanowires using electron-beam lithography. We demonstrate that, in difference from conventional macroscopic junctions, the fabricated self-assembled nanowire junction devices exhibit tunable nonlinear electrical characteristics and a signature of ballistic electron transport. ...
Tópico(s): Semiconductor materials and devices
2008 - American Chemical Society | Nano Letters
Dmitry Suyatin, Claes Thelander, Mats Björk, Ivan Maximov, Lars Samuelson,
We have studied the formation of ohmic contacts to InAs nanowires by chemical etching and passivation of the contact areas in an ammonium polysulfide, (NH4)2Sx, water solution. The nanowires were exposed to different dilution levels of the (NH4)2Sx solution before contact metal evaporation. A process based on a highly diluted (NH4)2Sx solution was found to be self-terminating, with minimal etching of the InAs. The stability of the contacts was investigated with electrical measurements as a function ...
Tópico(s): Semiconductor materials and interfaces
2007 - IOP Publishing | Nanotechnology
Jie Sun, Daniel Wallin, P. Brusheim, Ivan Maximov, Z.-G. Wang, H. Q. Xu,
Three-terminal ballistic junctions (TBJs) are fabricated from a high-mobility InP/In0.75Ga0.25As heterostructure by electron-beam lithography. The voltage output from the central branch is measured as a function of the voltages applied to the left and right branches of the TBJs. The measurements show that the TBJs possess an intrinsic nonlinearity. Based on this nonlinearity, a novel room-temperature functional frequency mixer and phase detector are realized. The TBJ frequency mixer and phase detector ...
Tópico(s): Semiconductor materials and devices
2007 - IOP Publishing | Nanotechnology
Karim C. Abbaspour, Jing Yang, Ivan Maximov, Rosi Siber, Konrad Bogner, Johanna Mieleitner, Juerg Zobrist, Raghavan Srinivasan,
Tópico(s): Groundwater flow and contamination studies
2006 - Elsevier BV | Journal of Hydrology
Gang Luo, Ivan Maximov, David Adolph, Mariusz Graczyk, Patrick Carlberg, Sara Ghatnekar‐Nilsson, Dan Hessman, Tao Zhu, Zhongfan Liu, H. Q. Xu, Lars Montelius,
We report on the realization of a novel interdigitated cantilever array with electrostatic control of the shape of the interdigitated array. It consists of an array of SiO2/metal double-finger cantilevers in a grating configuration together with an electrical connection part. The complete grating structure is fabricated with nanoimprint lithography, UV lithography and reactive ion etching. The patterns of the cantilever arrays are defined by nanoimprint lithography. The electrical contact pads are ...
Tópico(s): Microfluidic and Capillary Electrophoresis Applications
2006 - IOP Publishing | Nanotechnology
Claudio Balocco, Aimin Song, Magnus Åberg, A. Forchel, T. González, J. Mateos, Ivan Maximov, M. Missous, A. A. Rezazadeh, Jan Saijets, Lars Samuelson, Daniel Wallin, Keith J. Williams, L. Worschech, H. Q. Xu,
By using arrays of nanowires with intentionally broken symmetry, we were able to detect microwaves up to 110 GHz at room temperature. This is, to the best of our knowledge, the highest speed that has been demonstrated in different types of novel electronic nanostructures to date. Our experiments showed a rather stable detection sensitivity over a broad frequency range from 100 MHz to 110 GHz. The novel working principle enabled the nanowires to detect microwaves efficiently without a dc bias. In ...
Tópico(s): Advancements in Semiconductor Devices and Circuit Design
2005 - American Chemical Society | Nano Letters
Aimin Song, M. Missous, P. Omling, Ivan Maximov, W. Seifert, Lars Samuelson,
Based on a nanometer-scale semiconductor channel with an intentionally broken geometric symmetry, we have realized a type of memory device that consists of only two terminals, rather than the minimum of three terminals in conventional semiconductor memories. The charge retention time is at least 10 h at cryogenic temperatures and a few minutes at room temperature. Furthermore, the simplicity of the design allows the active part of the devices to be made in a single nanolithography step which, along ...
Tópico(s): Quantum and electron transport phenomena
2005 - American Institute of Physics | Applied Physics Letters
H. Q. Xu, Ivan Shorubalko, Daniel Wallin, Ivan Maximov, P. Omling, Lars Samuelson, W. Seifert,
In this letter, we demonstrate the realization of novel diodes, triodes, and logic gates with three-terminal ballistic junctions (TBJs) made from a semiconductor heterostructure. The approach exploits the ballistic nature of electron transport, which has emerged in the nanostructures. Importantly, we show that TBJs function as logic AND gates and can be used to construct other compound logic gates, such as NAND gates with voltage gain, when combined with a point contact (an inverter). The demonstrated ...
Tópico(s): Quantum and electron transport phenomena
2004 - Institute of Electrical and Electronics Engineers | IEEE Electron Device Letters