Read by QxMD icon Read

Applied Physics Letters

Taesoo Kim, Elenita Palmiano, Ru-Ze Liang, Hanlin Hu, Banavoth Murali, Ahmad R Kirmani, Yuliar Firdaus, Yangqin Gao, Arif Sheikh, Mingjian Yuan, Omar F Mohammed, Sjoerd Hoogland, Pierre M Beaujuge, Edward H Sargent, Aram Amassian
Monolithically integrated hybrid tandem solar cells that effectively combine solution-processed colloidal quantum dot (CQD) and organic bulk heterojunction subcells to achieve tandem performance that surpasses the individual subcell efficiencies have not been demonstrated to date. In this work, we demonstrate hybrid tandem cells with a low bandgap PbS CQD subcell harvesting the visible and near-infrared photons and a polymer:fullerene-poly (diketopyrrolopyrrole-terthiophene) (PDPP3T):[6,6]-phenyl-C60-butyric acid methyl ester (PC61BM)-top cell absorbing effectively the red and near-infrared photons of the solar spectrum in a complementary fashion...
May 29, 2017: Applied Physics Letters
Radhika K Poduval, Sacha Noimark, Richard J Colchester, Thomas J Macdonald, Ivan P Parkin, Adrien E Desjardins, Ioannis Papakonstantinou
All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS)...
May 29, 2017: Applied Physics Letters
David Cooper, Nicolas Bernier, Jean-Luc Rouvière, Yun-Yu Wang, Weihao Weng, Anita Madan, Shogo Mochizuki, Hemanth Jagannathan
Precession electron diffraction has been used to systematically measure the deformation in Si/SiGe blanket films and patterned finFET test structures grown on silicon-on-insulator type wafers. Deformation maps have been obtained with a spatial resolution of 2.0 nm and a precision of ±0.025%. The measured deformation by precession diffraction for the blanket films has been validated by comparison to energy dispersive x-ray spectrometry, X-Ray diffraction, and finite element simulations. We show that although the blanket films remain biaxially strained, the patterned fin structures are fully relaxed in the crystallographic planes that have been investigated...
May 29, 2017: Applied Physics Letters
Nanxi Li, Zhan Su, Purnawirman, E Salih Magden, Christopher V Poulton, Alfonso Ruocco, Neetesh Singh, Matthew J Byrd, Jonathan D B Bradley, Gerald Leake, Michael R Watts
In an optical interconnect circuit, microring resonators (MRRs) are commonly used in wavelength division multiplexing systems. To make the MRR and laser synchronized, the resonance wavelength of the MRR needs to be thermally controlled, and the power consumption becomes significant with a high-channel count. Here, we demonstrate an athermally synchronized rare-earth-doped laser and MRR. The laser comprises a Si3N4 based cavity covered with erbium-doped Al2O3 to provide gain. The low thermo-optic coefficient of Al2O3 and Si3N4 and the comparable thermal shift of the effective index in the laser and microring cross-sections enable lasing and resonance wavelength synchronization over a wide range of temperatures...
May 22, 2017: Applied Physics Letters
James Froberg, Vidura Jayasooriya, Seungyong You, Dharmakeerthi Nawarathna, Yongki Choi
Nanoelectronic devices integrated with dielectrophoresis (DEP) have been promoted as promising platforms for trapping, separating, and concentrating target biomarkers and cancer cells from a complex medium. Here, we visualized DEP and DEP gradients in conventional nanoelectronic devices by using multi-pass atomic force microcopy techniques. Our measurements directly demonstrated a short range DEP only at sharp step edges of electrodes, frequency dependent DEP polarity, and separation distance dependent DEP strength...
May 15, 2017: Applied Physics Letters
Zhaojiang Chen, Yang Zhang, Shiyang Li, Xuan-Ming Lu, Wenwu Cao
The frequency dependence of the coercive field Ec in [001]c poled 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystals was investigated as a function of frequency f from 0.01 Hz to 5 MHz. Ec was found to be proportional to [Formula: see text] as predicted by the Ishibashi and Orihara model, but our results showed two frequency regimes separated at around 1.0 MHz with different β values. This change of switching kinetics may be due to the presence of slower relaxation times for non-180° domain switching and heterogeneous nucleation of polar nanoregions, whose contribution to polarization reversal is frozen out beyond 1...
May 15, 2017: Applied Physics Letters
Ai Isohashi, P V Bui, D Toh, S Matsuyama, Y Sano, K Inagaki, Y Morikawa, K Yamauchi
Chemical etching of SiC was found to proceed in pure water with the assistance of a Pt catalyst. A 4H-SiC (0001) wafer was placed and slid on a polishing pad in pure water, on which a thin Pt film was deposited to give a catalytic nature. Etching of the wafer surface was observed to remove protrusions preferentially by interacting with the Pt film more frequently, thus flattening the surface. In the case of an on-axis wafer, a crystallographically ordered surface was obtained with a straight step-and-terrace structure, the height of which corresponds to that of an atomic bilayer of Si and C...
May 15, 2017: Applied Physics Letters
Jiang Zhu, Yusi Miao, Li Qi, Yueqiao Qu, Youmin He, Qiang Yang, Zhongping Chen
Shear wave measurements for the determination of tissue elastic properties have been used in clinical diagnosis and soft tissue assessment. A shear wave propagates as a transverse wave where vibration is perpendicular to the wave propagation direction. Previous transverse shear wave measurements could detect the shear modulus in the lateral region of the force; however, they could not provide the elastic information in the axial region of the force. In this study, we report the imaging and quantification of longitudinal shear wave propagation using optical coherence tomography to measure the elastic properties along the force direction...
May 15, 2017: Applied Physics Letters
David Maresca, Anupama Lakshmanan, Audrey Lee-Gosselin, Johan M Melis, Yu-Li Ni, Raymond W Bourdeau, Dennis M Kochmann, Mikhail G Shapiro
Ultrasound imaging is widely used to probe the mechanical structure of tissues and visualize blood flow. However, the ability of ultrasound to observe specific molecular and cellular signals is limited. Recently, a unique class of gas-filled protein nanostructures called gas vesicles (GVs) was introduced as nanoscale (∼250 nm) contrast agents for ultrasound, accompanied by the possibilities of genetic engineering, imaging of targets outside the vasculature and monitoring of cellular signals such as gene expression...
February 13, 2017: Applied Physics Letters
Gobind Basnet, Krishna R Panta, Prem S Thapa, Bret N Flanders
This paper describes the electrochemical growth of branchless gold nanoribbons with ∼40 nm × ∼300 nm cross sections and >100 μm lengths (giving length-to-thickness aspect ratios of >10(3)). These structures are useful for opto-electronic studies and as nanoscale electrodes. The 0.75-1.0 V voltage amplitude range is optimal for branchless ribbon growth. Reduced amplitudes induce no growth, possibly due to reversible redox chemistry of gold at reduced amplitudes, whereas elevated amplitudes, or excess electrical noise, induce significant side-branching...
February 13, 2017: Applied Physics Letters
T Vemulkar, E N Welbourne, R Mansell, D C M C Petit, R P Cowburn
In this article, we demonstrate the magneto-mechanic behavior in a fluid environment of perpendicularly magnetized microdiscs with antiferromagnetic interlayer coupling. When suspended in a fluid and under the influence of a simple uniaxial applied magnetic field sequence, the microdiscs mechanically rotate to access the magnetic saturation processes that are either that of the easy axis, hard axis, or in-between the two, in order to lower their energy. Further, these transitions enable the magnetic particles to form reconfigurable magnetic chains, and transduce torque from uniaxial applied fields...
January 23, 2017: Applied Physics Letters
D Sheng, A R Perry, S P Krzyzewski, S Geller, J Kitching, S Knappe
We report on the development of a microfabricated atomic magnetic gradiometer based on optical spectroscopy of alkali atoms in the vapor phase. The gradiometer, which operates in the spin-exchange relaxation free regime, has a length of 60 mm and cross sectional diameter of 12 mm, and consists of two chip-scale atomic magnetometers which are interrogated by a common laser light. The sensor can measure differences in magnetic fields, over a 20 mm baseline, of 10 fT/[Formula: see text] at frequencies above 20 Hz...
January 16, 2017: Applied Physics Letters
Nadia C Lara, Asad A Haider, Lon J Wilson, Steven A Curley, Stuart J Corr
Aqueous and nanoparticle-based solutions have been reported to heat when exposed to an alternating radiofrequency (RF) electric-field. Although the theoretical models have been developed to accurately model such a behavior given the solution composition as well as the geometrical constraints of the sample holder, these models have not been investigated across a wide-range of solutions where the dielectric properties differ, especially with regard to the real permittivity. In this work, we investigate the RF heating properties of non-aqueous solutions composed of ethanol, propylene glycol, and glycine betaine with and without varying amounts of NaCl and LiCl...
January 2, 2017: Applied Physics Letters
Jiang You, Ang Li, Congwu Du, Yingtian Pan
Ultrahigh-resolution optical coherence Doppler tomography (μODT) demonstrates great potential for quantitative blood flow imaging owing to its large field of view and capillary resolution. However, μODT only detects the axial flow velocity and requires Doppler angle correction to retrieve the absolute velocity. Although methods for Doppler angle tracking of single or few large vessels have been reported, a method that enables angle correction of the entire 3D microvascular networks remains a challenge. Here, we present a method based on eigenvalue analysis of 3D Hessian matrix to retrieve the orientation of each tubular vessel...
January 2, 2017: Applied Physics Letters
Anupama Bhat, Lance W Edwards, Xiao Fu, Dillon L Badman, Samuel Huo, Albert J Jin, Qi Lu
Gold nanoparticles (AuNPs) have been increasingly integrated in biological systems, making it imperative to understand their interactions with cell membranes, the first barriers to be crossed to enter cells. Herein, liposomes composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) as a model membrane system were treated with citrate stabilized AuNPs from 5 to 30 nm at various concentrations. The fluorescence shifts of Laurdan probes reveal that AuNPs in general made liposomes more fluidic. The increased fluidity is expected to result in an increased surface area, and thus liposome shape changes from circular to less circular, which was further confirmed with fluorescence microscopy...
December 26, 2016: Applied Physics Letters
Pol Grasland-Mongrain, Yuankang Lu, Frederic Lesage, Stefan Catheline, Guy Cloutier
This article describes the generation of elastic shear waves in a soft medium using a laser beam. Our experiments show two different regimes depending on laser energy. Physical modeling of the underlying phenomena reveals a thermoelastic regime caused by a local dilatation resulting from temperature increase, and an ablative regime caused by a partial vaporization of the medium by the laser. Computed theoretical displacements are close to experimental measurements. A numerical study based on the physical modeling gives propagation patterns comparable to those generated experimentally...
November 28, 2016: Applied Physics Letters
Janggun Jo, Xinmai Yang
The enhanced heating effect during the combination of high-intensity focused ultrasound (HIFU) and low-optical-fluence laser illumination was investigated by using an in vivo murine animal model. The thighs of murine animals were synergistically irradiated by HIFU and pulsed nano-second laser light. The temperature increases in the target region were measured by a thermocouple under different HIFU pressures, which were 6.2, 7.9, and 9.8 MPa, in combination with 20 mJ/cm(2) laser exposures at 532 nm wavelength...
November 21, 2016: Applied Physics Letters
Nezih Tolga Yardimci, Hong Lu, Mona Jarrahi
We present a high-power and broadband photoconductive terahertz emitter operating at telecommunication optical wavelengths, at which compact and high-performance fiber lasers are commercially available. The presented terahertz emitter utilizes an ErAs:InGaAs substrate to achieve high resistivity and short carrier lifetime characteristics required for robust operation at telecommunication optical wavelengths. It also uses a two-dimensional array of plasmonic nano-antennas to offer significantly higher optical-to-terahertz conversion efficiencies compared to the conventional photoconductive emitters, while maintaining broad operation bandwidths...
November 7, 2016: Applied Physics Letters
Junwen Li, Paul M Haney
We study the circular photogalvanic effect in the organometal halide perovskite solar cell absorber CH3NH3PbI3. The calculated photocurrent density for a system with broken inversion symmetry is about 10(-9) A/W, comparable to the previously studied quantum well and bulk Rashba systems. The circular photogalvanic effect relies on inversion symmetry breaking, so that by tuning the optical penetration depth, the degree of inversion symmetry breaking can be probed at different depths from the sample surface. We propose that measurements of this effect may clarify the presence or absence of inversion symmetry, which remains a controversial issue and has been argued to play an important role in the high conversion efficiency of this material...
November 2016: Applied Physics Letters
Chunlong Fei, Ying Li, Benpeng Zhu, Chi Tat Chiu, Zeyu Chen, Di Li, Yintang Yang, K Kirk Shung, Qifa Zhou
This paper reports on contactless microparticle manipulation including single-particle controlled trapping, transportation, and patterning via single beam acoustic radiation forces. As the core component of single beam acoustic tweezers, a needle type ultrasonic transducer was designed and fabricated with center frequency higher than 300 MHz and -6 dB fractional bandwidth as large as 64%. The transducer was built for an f-number close to 1.0, and the desired focal depth was achieved by press-focusing technology...
October 24, 2016: Applied Physics Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"