High-throughput, sheathless, magnetophoretic separation of magnetic and non-magnetic particles with a groove-based channel
The separation of target objects conjugated with magnetic particles is a significant application in biomedicine and clinical diagnosis. Conventionalmagnetophoresis-baseddevices use a sheathflow to pre-focus the particles into a single stream and typically operate at a lowflow rate. We demonstrate in this work a high-throughput, sheathless,magnetophoretic separation of magnetic and non-magnetic beads in a groove-based channel, and also report on an interesting phenomenon where the same magnetic beads in the same microchannel, but with different setups, has a different particle tracing; a binary mixture of magnetic and non-m...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: S. Yan, J. Zhang, D. Yuan, Q. Zhao, J. Ma and W. H. Li Source Type: research
InAs/GaSb-on-insulator single channel complementary metal-oxide-semiconductor transistors on Si structure
We demonstrate a single channel III –V complementarymetal-oxide-semiconductor(CMOS)transistors by ultrathin body InAs/GaSb-on-insulator (-OI) channels on Si. The ultrathinInAs layers with the quantum confinement and tight gate-control of the identical InAs/GaSb-OI channel can realize III –VCMOS operation. The quantum well InAs/GaSb-OI on Sistructures with the proper thickness of theInAs andGaSb layers can allow us to operate both n-channel and p-channelmetal-oxide-semiconductor field-effecttransistors (n-MOSFETs and p-MOSFETs) with high channelmobilities in an identical InAs/GaSb-OItransistor. TheInAs thickness needs t...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Masafumi Yokoyama, Haruki Yokoyama, Mitsuru Takenaka and Shinichi Takagi Source Type: research
Experimental evidence of the anti-parallel arrangement of methylammonium ions in perovskites
Orientation arrangement of methylammonium ions in hybrid organic −inorganicperovskite is still under debate because their tendency for alignment is expected to give rise to eitherferroelectric or anti-ferroelectric behavior, which may influence theperovskitedevice performance. To resolve the debate surrounding the alignment of the organic cations inperovskitematerials, we studied the dipole orientation byanalysing the dielectric properties of thematerial. The dielectricpermittivity has been investigated as a function of temperature with the dataanalysed using the Kirkwood –Fröhlich–Onsager theory. From these results...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Yan-Fang Chen, Yu-Tang Tsai, Dario M. Bassani and Lionel Hirsch Source Type: research
Lowest energy Frenkel and charge transfer exciton intermixing in one-dimensional copper phthalocyanine molecular lattice
We report the results of the combined experimental and theoretical studies of the low-lyingexciton states in crystallinecopper phthalocyanine. We derive the eigenenergyspectrum for the two lowest intramolecularFrenkel excitons coupled to the intermolecularcharge transferexciton state and compare it with temperature dependent optical absorptionspectra measured experimentally, to obtain the parameters of the Frenkel-charge-transferexciton intermixing. The twoFrenkel exciton states are spaced apart by 0.26 eV, and thecharge transferexciton state is 50 meV above the lowestFrenkel exciton. BothFrenkel excitons are strongl...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: I. V. Bondarev, A. Popescu, R. A. Younts, B. Hoffman, T. McAfee, D. B. Dougherty, K. Gundogdu and H. W. Ade Source Type: research
Anomalous specific heats of metallic nanocrystals induced by surface oxidation
Although thelow-temperaturespecific heat in metallicnanocrystals has been extensively demonstrated to be always enhanced due to thesurfacephonon softening, it is revealed here to be anomalously depressed by thesurface oxidation so that the excessspecific heat can be either positive or negative as a function of temperature with respect to the counterparts of thebulk crystals. The background mechanism has been theoretically deduced to well explain these experimental phenomena by calculating and comparing the vibrational densities of states (VDOS) of face-centered-cubic-aluminum (fcc-Al) and amorphous-alumina (a-Al2O3)nanopar...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Haile Lei, Jiangshan Luo, Jun Li, Fei Dai, Mengsheng Yang, Jicheng Zhang and Jingmin Zhang Source Type: research
Ultrafast and ultrasensitive phototransistors based on few-layered HfSe2
Two-dimensional layeredmaterials have exhibited great potential in electronic and optoelectronic applications, because of their unique chemical and physicalproperties. Recently, Hf-based transition metal dichalcogenides are predicted to own high room temperaturemobility and are attracting increasing interest. However, only few experimental investigations are reported hitherto. In this paper, we demonstrate ultrafast and ultrasensitive back-gated HfSe2phototransistors. Au-contacted HfSe2phototransistors display a high on/off ratio of 106 and modestmobilities in the range of 2.6 –6.5 cm2 V−1 s−1. Additionally, thepho...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Lei Yin, Kai Xu, Yao Wen, Zhenxing Wang, Yun Huang, Feng Wang, Tofik Ahmed Shifa, Ruiqing Cheng, He Ma and Jun He Source Type: research
First-principles calculations of the near-edge optical properties of β-Ga2O3
We use first-principles calculations based on many-body perturbationtheory to investigate the near-edge electronic andoptical properties of β-Ga2O3. The fundamentalband gap is indirect, but the minimum direct gap is only 29 meV higher inenergy, which explains the strong near-edgeabsorption. Our calculations verify the anisotropy of theabsorption onset and explain the range (4.4 –5.0 eV) of experimentally reportedband-gap values. Our results for the radiative recombination rate indicate that intrinsic light emission in the deep-ultra-violet (UV) range is possible in this indirect-gap semiconductor at high excitation...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Kelsey A. Mengle, Guangsha Shi, Dylan Bayerl and Emmanouil Kioupakis Source Type: research
Calcium impurity as a source of non-radiative recombination in (In,Ga)N layers grown by molecular beam epitaxy
Ca as an unintentional impurity has been investigated in III-nitride layersgrown bymolecular beam epitaxy(MBE). It is found that Ca originates from the substratesurface, even if carefulcleaning and rinsing procedures are applied. The initial Casurface coverage is ∼1012 cm−2, which is consistent with previous reports onGaAs and silicon wafers. At the onset ofgrowth, the Ca species segregates at thegrowth front while incorporating at low levels. The incorporation rate is strongly temperature dependent. It is about 0.03% at 820 °C and increases by two orders of magnitude when the temperature is reduced to 600 °C...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: E. C. Young, N. Grandjean, T. E. Mates and J. S. Speck Source Type: research
Electronic properties and native point defects of high efficient NO oxidation catalysts SmMn2O5
Mn-based oxide SmMn2O5 exhibits greatcatalytic performance in NOoxidation [Wanget al., Science337, 832 (2012)]. Nevertheless, the fundamental understanding of SmMn2O5 properties is so far not fully accessible. Here, the SmMn2O5nanoparticles are synthesized through hydrothermal methods, and the pure phase of triclinic SmMn2O5 is characterized by high-resolution tunneling electron microscope andX-ray diffraction. Furthermore, the X-ray photoelectron spectroscopy,absorption,photoluminescencespectra(PL), anddensity functional theory based first-principles calculations are employed to explore the fundamental electronic structur...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Hao-Bo Li, Zhi Yang, Jieyu Liu, Xiaolong Yao, Ka Xiong, Hui Liu, Wei-Hua Wang, Feng Lu and Weichao Wang Source Type: research
Copper dry etching by sub-atmospheric-pressure pure hydrogen glow plasma
Copper(Cu) dryetching is demonstrated using a narrow-gap hydrogenplasma generated at 13.3 kPa (100 Torr) for applications in theCu wiring technology of integrated circuits. A localized hydrogenplasma is generated around the apex of a fine pipeelectrode. TheCuetching can be observed only when the process gas contains hydrogen, and theetching rates decrease with decreased hydrogen concentration. Theplasma heating effect owing toplasma localization is negligible for theCuetching because noetching occurs in the presence of pure N2plasma whose volume is almost equal to that of the pure H2plasma. Furthermore, the influences...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Hiromasa Ohmi, Jumpei Sato, Tatsuya Hirano, Yusuke Kubota, Hiroaki Kakiuchi and Kiyoshi Yasutake Source Type: research
In-situ observation of self-cleansing phenomena during ultra-high vacuum anneal of transition metal nitride thin films: Prospects for non-destructive photoelectron spectroscopy
Self-cleansing of transition metal nitrides is discovered to take place during ultra-high vacuum annealing of TiN, NbN, and VN thin films. Native oxide layers from air exposure disappear after isothermal anneal at 1000 °C. Also, for TiN, the Ti 2p and N 1s X-ray photoelectron spectra(XPS) recorded after the anneal are identical to those obtained fromin-situgrown andanalyzedepitaxial TiN(001). These unexpected effects are explained by oxide decomposition in combination with N-replenishing of the nitride duringrecrystallization. The finding opens up new possibilities for true bonding assignments through non-destructiveXP...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: G. Greczynski and L. Hultman Source Type: research
Active control of electromagnetically induced transparency with dual dark mode excitation pathways using MEMS based tri-atomic metamolecules
We report experimental results of the active switching of electromagnetically induced transparency (EIT) analogue by controlling the dark mode excitation pathways in amicroelectromechanical system based tri-atomic metamolecule, operating in the terahertzspectral region. The tri-atomic metamolecule consists of two bright cut wireresonators (CWRs) on either side of the dark split ringresonators (SRRs). Each of the CWRs can independently excite the dark inductive-capacitive resonance mode of the SRRs through inductive coupling, and this allows for the dual pathways of dark mode excitation. The CWRs are made movable along the ...
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Prakash Pitchappa, Manukumara Manjappa, Chong Pei Ho, Ranjan Singh, Navab Singh and Chengkuo Lee Source Type: research
Extracting fundamental transverse mode operation in broad area quantum cascade lasers
We report a method of suppressing the high order transverse modes that can extract the fundamental mode and provide emission along the optical axis. By generating a lateral constriction in thewaveguide in the form of short trenches defined by thefocused ion beammilling technique, we report broad areadevices in which most of the power is contained in a near diffraction-limitedbeam that provides highbrightness. (Source: Applied Physics Letters)
Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: R. Kaspi, S. Luong, C. Yang, C. Lu, T. C. Newell and T. Bate Source Type: research
Laser-enhanced high-intensity focused ultrasound heating in an in vivo small animal model
The enhancedheatingeffect during the combination of high-intensity focused ultrasound (HIFU) and low-optical-fluence laserillumination was investigated by using anin vivo murine animal model. The thighs of murine animals were synergisticallyirradiated by HIFU and pulsed nano-second laser light. Thetemperature increases in the target region weremeasured by a thermocouple under different HIFUpressures, which were 6.2, 7.9, and 9.8 MPa, in combination with 20 mJ/cm2 laser exposures at 532 nm wavelength. In comparison with conventional laser therapies, the laser fluence used here is at least one order of magnitude lower....
Source: Applied Physics Letters - November 22, 2016 Category: Physics Authors: Janggun Jo and Xinmai Yang Source Type: research
Rectification magnetoresistance device: Experimental realization and theoretical simulation
A unique technique has been proposed to realizerectificationmagnetoresistance (RMR) by combining a commercial diode and amagnetoresistance component in parallel. The observed RMR could be greatly tuned in a wide range by applyingdirect current andalternating current simultaneously to the device. Moreover, a quantitative theoretical model has been established, which well explained both the observed RMR and the electrical manipulation behavior. The highly tunable RMR and the correlated magnetoelectric functionalities provide an alternative route for developing multi-functional spintronics devices. (Source: Applied Physics Letters)
Source: Applied Physics Letters - November 22, 2016 Category: Physics Authors: Kun Zhang, Qikun Huang, Yi Yan, Xiaolin Wang, Jing Wang, Shishou Kang and Yufeng Tian Source Type: research
