Lithographic resolution enhancement of a maskless lithography system based on a wobulation technique for flow lithography
We present a method for improving the lithographic resolution of digital micromirror devices for flow-lithography using a wobulation technique. While maintaining the area ofUV exposure, the lithographic resolution was improved using a wobulation technique, which is a large screen display technique that enhances resolution via overlapping pixels by half a pixel. The edges of a diagonalpattern in amicrostructure were smoothlygenerated with additional sub-patterns compared to conventional singlepattern-exposure. In addition, thesurface roughness of themicrostructure was improved because the gaps between pixels were filled by ...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Kibeom Kim, Sangkwon Han, Jinsik Yoon, Sunghoon Kwon, Hun-Kuk Park and Wook Park Source Type: research
Control surface wettability with nanoparticles from phase-change materials
Thewetting state ofsurfaces can be controlled physically from the highlyhydrophobic tohydrophilic states using the amorphous-to-crystallinephase transition of Ge2Sb2Te5 (GST) nanoparticles as surfactant. Indeed, contact angle measurements show that by increasing thesurface coverage of the amorphous nanoparticles the contact angle increases to high values ∼140°, close to the superhydrophobic limit. However, for crystallized nanoparticle assemblies after thermal annealing, the contact angle decreases down to ∼40° (significantly lower than that of the bare substrate) leading to an increasedhydrophilicity. Moreover, the ...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: G. H. ten Brink, P. J. van het Hof, B. Chen, M. Sedighi, B. J. Kooi and G. Palasantzas Source Type: research
Erratum: “A charge inverter for III-nitride light-emitting diodes” [Appl. Phys. Lett. 108, 133502 (2016)]
(Source: Applied Physics Letters)
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Zi-Hui Zhang, Yonghui Zhang, Wengang Bi, Chong Geng, Shu Xu, Hilmi Volkan Demir and Xiao Wei Sun Source Type: research
Lattice-matched Cu2ZnSnS4/CeO2 solar cell with open circuit voltage boost
We report a reproducible enhancement of the open circuit voltage in Cu2ZnSnS4solar cells by introduction of a very thin CeO2 interlayer between the Cu2ZnSnS4 absorber and the conventionalCdS buffer. CeO2, a non-toxic earth-abundant compound, has a nearly optimal band alignment with Cu2ZnSnS4 and the two materials are lattice-matched within 0.4%. This makes it possible to achieve anepitaxial interface whengrowing CeO2 by chemical bathdeposition at temperatures as low as 50 °C. The open circuit voltage improvement is then attributed to a decrease in the interface recombination rate through formation of a high-quality het...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Andrea Crovetto, Chang Yan, Beniamino Iandolo, Fangzhou Zhou, John Stride, J ørgen Schou, Xiaojing Hao and Ole Hansen Source Type: research
Plasma treatment effect on angiogenesis in wound healing process evaluated in vivo using angiographic optical coherence tomography
Non-thermalatmospheric pressure plasma holds promise for promoting wound healing. However, plasma-induced angiogenesis, which is important to better understand the underlying physics ofplasma treatment effect on wound healing, remains largely unknown. We therefore evaluated the effect of non-thermalplasma on angiogenesis during wound healing through longitudinal monitoring over 30 days using non-invasive angiographicoptical coherence tomographyimagingin vivo. We demonstrate that the plasma-treated vascular wound area of mouse ear was noticeably decreased as compared to that of control during the early days in the wound hea...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: D. W. Kim, T. J. Park, S. J. Jang, S. J. You and W. Y. Oh Source Type: research
Demonstration of flexible thin film transistors with GaN channels
We report on thethin film transistors(TFTs) withGallium Nitride(GaN) channels directly fabricated on flexible substrates.GaNthin films aregrown by hollow cathode plasma assistedatomic layer deposition (HCPA-ALD) at 200 °C.TFTs exhibit 103 on-to-off current ratios and are shown to exhibit propertransistor saturation behavior in their output characteristics. Gate bias stress tests reveal that flexibleGaNTFTs have extremely stable electrical characteristics. Overall fabrication thermal budget is below 200 °C, the lowest reported for theGaN basedtransistors so far. (Source: Applied Physics Letters)
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: S. Bolat, Z. Sisman and A. K. Okyay Source Type: research
Perovskite heterojunction based on CH3NH3PbBr3 single crystal for high-sensitive self-powered photodetector
Perovskitesingle crystals exhibit extraordinary optoelectronic performances due to their advantages such as low trap-state densities, long carrier diffusion, and large absorption coefficient, and thus,photodetectors based onperovskitesingle crystals have attracted much research interest. Unlike the reported one-componentsingle-crystalperovskitephotodetectors, here, we have developed a facile two-step approach to fabricate a core-shellheterojunction based on the CH3NH3PbBr3single crystal. Aphotodetector made of the as-preparedperovskiteheterojunction renders the feature of self-power attributed to a built-in electric field ...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Min Cao, Jiyu Tian, Zhi Cai, Lan Peng, Lei Yang and Dacheng Wei Source Type: research
Direct observation of the M2 phase with its Mott transition in a VO2 film
In VO2, the explicit origin of theinsulator-to-metal transition is still disputable between Peierls and Mottinsulators. Along with the controversy, its second monoclinic (M2) phase has received considerable attention due to the presence of electron correlation in undimerizedvanadium ions. However, the origin of the M2 phase is still obscure. Here, we study a granular VO2 film using conductive atomic force microscopy andRaman scattering. Upon the structuraltransition from monoclinic to rutile, we observe directly an intermediate state showing the coexistence of monoclinic M1 and M2 phases. The conductivity near thegrain bou...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Hoon Kim, Tetiana V. Slusar, Dirk Wulferding, Ilkyu Yang, Jin-Cheol Cho, Minkyung Lee, Hee Cheul Choi, Yoon Hee Jeong, Hyun-Tak Kim and Jeehoon Kim Source Type: research
Nano-gap between a gold tip and nanorod for polarization dependent surface enhanced Raman scattering
We demonstrate experimentally that a nano-gap could be constructed by using ascanning probe microscope to allow agold tip to approach agoldnanorod immobilized on a glass coverslip. The nano-gap can enhance Raman scattering ofgraphene sandwiched between the tip and thenanorod. The Raman intensity was strongly dependent on the incident lightpolarization. Here, linear, radial, azimuthal, and intermediate states between radial and azimuthalpolarization were investigated and compared in detail. The maximumsurface-enhanced Raman scattering effect of the nano-gap occurred for the intermediate states between the radial and azimuth...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Zhengmin Cao, Yingbo He, Yuqing Cheng, Jingyi Zhao, Guantao Li, Qihuang Gong and Guowei Lu Source Type: research
Transport properties of chemically synthesized MoS2 – Dielectric effects and defects scattering
We report on the electrical characterization of synthetic, large-area MoS2 layers obtained by the sulfurization technique. The effects ofdielectric encapsulation and localized defect states on the intrinsictransport properties are explored with the aid of temperature-dependent measurements. We study the effect ofdielectric environment by transferring as-grown MoS2films into differentdielectrics such as SiO2, Al2O3, HfO2, and ZrO2 with increasingdielectric permittivity. Electrical data are collected on a statistically-relevantdevice ensemble and allow to assessdevice performances on a large scale assembly. Ourdevices show r...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Massimo Mongillo, Daniele Chiappe, Goutham Arutchelvan, Inge Asselberghs, Marta Perucchini, Mauricio Manfrini, Dennis Lin, Cedric Huyghebaert and Iuliana Radu Source Type: research
The influence of magnetocrystalline anisotropy on the magnetocaloric effect: A case study on Co2B
The influence of magnetocrystallineanisotropy on themagnetocaloric effect (MCE) was studied onsingle crystals of Co2B and compared to measurements onpolycrystalline samples. Large differences in adiabatictemperature changeΔTad and magneticentropy changeΔSM were found along the different crystallographic directions. Themagnetocaloric effect differs by 40% in the case ofΔTad in a field change of 1.9 T when applying the field along the hard axis and easy plane of magnetization. In the case ofΔSM, the values differ 50% and 35% from each other in field changes of 1 and 1.9 T, respectively. It was found that thisanisot...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: M. Fries, K. P. Skokov, D. Yu. Karpenkov, V. Franco, S. Ener and O. Gutfleisch Source Type: research
Ruddlesden-Popper interface in correlated manganite heterostructures induces magnetic decoupling and dead layer reduction
We report on theinterface engineering in correlated manganiteheterostructures by octahedral decoupling using embedded stacks of atomic layers that form the Ruddlesden-Popperstructure. A room temperature magnetic decoupling was achieved through deposition of a (SrO)2–TiO2–(SrO)2 sequence of atomic layers at theinterface between La0.7Sr0.3MnO3 and La0.7Sr0.3Mn0.9Ru0.1O3films. Moreover, the narrowing of the interfacial dead layer in ultrathin La0.7Sr0.3MnO3films was demonstrated by insertion of a single (SrO)2 rock-salt layer at theinterface with the SrTiO3(100) substrate. The obtained results are discussed based on the s...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: A. Belenchuk, O. Shapoval, V. Roddatis, V. Bruchmann-Bamberg, K. Samwer and V. Moshnyaga Source Type: research
High carrier mobility of Sn-doped polycrystalline-Ge films on insulators by thickness-dependent low-temperature solid-phase crystallization
To realize the advancedthin-film transistors(TFTs), high-carrier-mobility semiconductorfilms on insulator structures should be fabricated with low-temperature processing conditions ( ≤500 °C). To achieve this, we investigated the solid-phase crystallization of amorphous-GeSnfilms on insulating substrates under a wide range of Sn concentrations (0% –20%),film thicknesses (30 –500 nm), and annealing temperatures (380–500 °C). Our results reveal that a Sn concentration close to the solid solubility of Sn inGe ( ∼2%) is effective in increasing the grain-size of poly-GeSn. In addition, we discovered that theca...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Taizoh Sadoh, Yuki Kai, Ryo Matsumura, Kenta Moto and Masanobu Miyao Source Type: research
Interplay between quantum well width and interface roughness for electron transport mobility in GaAs quantum wells
We report transportmobility measurements for clean, two-dimensional (2D) electron systems confined to GaAsquantum wells(QWs),grown viamolecular beam epitaxy, in two families of structures, a standard, symmetrically doped GaAs set ofQWs with Al0.32Ga0.68As barriers and one with additional AlAscladding surrounding theQWs. Our results indicate that themobility in narrowQWs with nocladding is consistent with existing theoretical calculations whereinterface roughness effects are softened by the penetration of the electronwave function into the adjacent low barriers. In contrast, data from AlAs-clad wells show a number of sample...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: D. Kamburov, K. W. Baldwin, K. W. West, M. Shayegan and L. N. Pfeiffer Source Type: research
Structure of the menisci of leaky dielectric liquids during electrically-assisted evaporation of ions
An understanding of the processes enabling field-assisted evaporation ofions from leakydielectric liquids, i.e.,liquids that are substantially less conductive thanliquid metals, has historically been elusive in comparison to those of conventional electrohydrodynamic emission modes such as that of the cone-jet. While selectionic liquids have been shown to yield nearly monodisperse beams of molecularions under certain conditions, the dearth of direct observation (visualization) and theoretical insight has precluded a fundamental appreciation for the inherent mechanics. In this paper, we present a family of equilibriummeniscu...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Chase Coffman, Manuel Mart ínez-Sánchez, F. J. Higuera and Paulo C. Lozano Source Type: research
