High power (60 mW) GaSb-based 1.9 μm superluminescent diode with cavity suppression element
Thecharacteristics and the fabrication of a 1.9 μm superluminescentdiode utilizing a cavity suppression element are reported. The strong suppression of reflections allows the device to reach high gain without any sign of lasing modes. The high gain enables strong amplifiedspontaneous emission and output power up to 60 mW in a single transverse mode. At high gain, thespectrum is centered around 1.9 μm and the full width at half maximum is as large as 60 nm. The power andspectralcharacteristics pave the way for demonstrating compact and efficient light sources for spectroscopy. In particular, the light source meet...
Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: Nouman Zia, Jukka Viheri älä, Riku Koskinen, Antti Aho, Soile Suomalainen and Mircea Guina Source Type: research
On the extraordinary strength of Prince Rupert's drops
Prince Rupert's drops (PRDs), also known as Batavian tears, have been in existence since the early 17th century. They are made of a silicate glass of a high thermal expansion coefficient and have the shape of a tadpole. Typically, the diameter of the head of a PRD is in the range of 5 –15 mm and that of the tail is 0.5 to 3.0 mm. PRDs have exceptional strength properties: the head of a PRD can withstand impact with a small hammer, or compression betweentungstencarbide platens to high loads of ∼15 000 N, but the tail can be broken with just finger pressure leading to catastrophic disintegration of the PRD. We sh...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: H. Aben, J. Anton, M. Õis, K. Viswanathan, S. Chandrasekar and M. M. Chaudhri Source Type: research
A multiple-selenization process for enhanced reproducibility of Cu2ZnSn(S,Se)4 solar cells
A multiple-selenization process for wet-chemically fabricated kesterite-type Cu2ZnSn(S,Se)4solar cells is reported that significantly improves the overall sample quality of the absorber layer and especially the reproducibility of devicecharacteristics. Conversion efficiencies of up to 7.2% are obtained. With this method, the absorber forms a very compact, hole- and crack-free layer and avoids the formation ofmultilayer ortrilayer structures. Mainly, the seriesresistance and therefore the short-circuit current can be stabilized, which leads to lower fluctuation of the energy conversion efficiency of thesolar cells on the sa...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Markus Neuwirth, Huijuan Zhou, Thomas Schnabel, Erik Ahlswede, Heinz Kalt and Michael Hetterich Source Type: research
Determining the vibrations between sensor and sample in SQUID microscopy
Vibrations can cause noise inscanning probe microscopies. Relative vibrations between the scanningsensor and the sample are important but can be more difficult to determine than absolute vibrations or vibrations relative to the laboratory. We measure the noise spectral density in a scanningSQUIDmicroscope as a function of position near a localized source of magnetic field and show that we can determine the spectra of all three components of the relative sensor-sample vibrations. This method is a powerful tool for diagnosing vibrational noise inscanning microscopies. (Source: Applied Physics Letters)
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Daniel Schiessl, John R. Kirtley, Lisa Paulius, Aaron J. Rosenberg, Johanna C. Palmstrom, Rahim R. Ullah, Connor M. Holland, Y.-K.-K. Fung, Mark B. Ketchen, Gerald W. Gibson Jr. and Kathryn A. Moler Source Type: research
Surface passivation and protection of Pt loaded multicrystalline pn+ silicon photocathodes by atmospheric plasma oxidation for improved solar water splitting
In the traditional methods such as atomic layer deposition and sputtering, a thin metal oxide layer was usuallydeposited before the loading of catalysts to protect Si photoelectrodes fromoxidation during solar water splitting, and this often results in the transfer of photogenerated carriers from Si to electrolyte more or less inhibited. We here use an atmosphericplasmaoxidation method to improve this. A SiO2 protective layer, also an effectivepassivation layer of Si to increase the life time of carriers, is fabricated on Pt loaded multicrystalline pn+-Siphotocathodes. Compared with the un-protected one, the energy convers...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Ronglei Fan, Chengshuang Tang, Yu Xin, Xiaodong Su, Xiaodong Wang and Mingrong Shen Source Type: research
A power-adjustable superconducting terahertz source utilizing electrical triggering phase transitions in vanadium dioxide
We report a practical superconducting terahertz (THz)source, comprising a stack of Bi2Sr2CaCu2O8 intrinsicJosephson junctions (IJJs) and a vanadium dioxide (VO2) tunableattenuator with coplanar interdigital contacts. The electrical triggeringphase transitions are observed not only at room temperature, but also at low temperatures, which provides a proof of the electrical triggering. Applying this, the VO2attenuator is implemented for the independent regulations on the emission powers from the IJJ THz emitter, remaining frequencies and temperatures unchanged. Theattenuation can be tuned smoothly and continuously within a co...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: L. Y. Hao, X. J. Zhou, Z. B. Yang, H. L. Zhang, H. C. Sun, H. X. Cao, P. H. Dai, J. Li, T. Hatano, H. B. Wang, Q. Y. Wen and P. H. Wu Source Type: research
Hybrid superconductor-quantum point contact devices using InSb nanowires
Proposals for studying topologicalsuperconductivity and Majoranabound states in ananowire proximity coupled tosuperconductors require thattransport in thenanowire isballistic. Previous works on hybrid nanowire-superconductor systems have shown evidence for Majoranabound states, but these experiments were also marked by disorder, which disruptsballistic transport. In this paper, we demonstrateballistic transport in theInSbnanowires interfaced directly withsuperconductingAl by observing quantized conductance at zero-magnetic field. Additionally, we demonstrate that thenanowire is proximity coupled to thesuperconducting conta...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: S. T. Gill, J. Damasco, D. Car, E. P. A. M. Bakkers and N. Mason Source Type: research
Self-modulated field electron emitter: Gated device of integrated Si tip-on-nano-channel
We report the featured gatedfield electron emission devices of Si nano-tips with individually integrated Si nano-channels and the interpretation of the related physics. A rational procedure was developed tofabricate the uniform integrated devices. The electrical and thermal conduction tests demonstrated that the Si nano-channel can limit both the current and heat flows. The integrated devices showed the specialties of self-enhancement and self-regulation. The heatresistance results in the heat accumulation at the tip-apex, inducing the thermally enhancedfield electron emission. The self-regulated effect of theelectrical re...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Zhijun Huang, Yifeng Huang, Zhangxu Pan, Juncong She, Shaozhi Deng, Jun Chen and Ningsheng Xu Source Type: research
Platinum (II) azatetrabenzoporphyrins for near-infrared organic light emitting diodes
This article describes a series ofplatinum (II) azatetrabenzoporphyrin emitters for near-infrared (NIR)organic light emitting diode(OLED) applications.Platinum (II) aza-triphenyltetrabenzoporphyrin (PtNTBP) results in a 72 nm shift in the photoluminescent(PL)emission spectrum to 842 nm compared to 770 nm of theplatinum (II) tetraphenyltetrabenzoporphyrin (PtTPTBP). Also, the full width at half maximum of theemission spectrum of PtNTBP was significantly narrowed to 27 nm compared to 40 nm for PtTPTBP. Themultilayer devicesfabricated by thermal vacuum evaporation process employing PtTPTBP, PtNTBP, and cis-PtN2TB...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: L. Huang, C. D. Park, T. Fleetham and J. Li Source Type: research
Simultaneous enhancement of conductivity and Seebeck coefficient in an organic Mott transistor
We report on the electrical conductivity and Seebeck coefficient of an electric-double-layertransistor based on an organic Mottinsulator. The measurements were performed along the two in-plane crystallographic axes (a andc) of the same device. While the Seebeck coefficient along thea-axis was decreased by electron or holedoping, the value along thec-axis was increased by holedoping. This is in contrast to the general trade-off relation between the conductivity and the Seebeck coefficient. The simultaneous enhancement of the conductivity and the Seebeck coefficient is attributed topseudogap formation in the hole-doped state...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Yoshitaka Kawasugi, Kazuhiro Seki, Yusuke Edagawa, Yoshiaki Sato, Jiang Pu, Taishi Takenobu, Seiji Yunoki, Hiroshi M. Yamamoto and Reizo Kato Source Type: research
X-ray and optical characterizations of DNA-mediated Janus nanostructures
Thestructural and optical properties of DNA-mediated Au-Ag Janusnanostructures (JNs) are comprehensively studied by X-ray and optical techniques. The theoretical model for small angleX-ray scattering of Au-Ag JNs is proposed, and the fitting process is outlined. A hybrid junction consists ofDNA andAg is introduced in order to reconcile the discrepancy between the experimental and simulated optical spectra of Au-Ag JNs. The physical origins and controlling factors of the localized surface plasmon resonance modes are determined, which lay the foundations for managing and exploiting the uniqueplasmonic properties of Au-Ag JNs...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Geng Wang, Lifeng Xu, Longlong Wu, Ke Meng, Xiao Wang, Zhou Liu, Chunhai Fan and Gang Chen Source Type: research
Cu passivation for integration of gap-filling ultralow-k dielectrics
For Cu/low-k interconnects, the reversed damascene is an alternative integration approach where the metal wires are patterned first and then the spacing filled with a flowabledielectric. In this paper, the replacement of a sacrificial template by gap-filling ultralow-kdielectrics is studied, focusing on yield and transport performance ( “replacement dielectric” scheme). On non-passivatedcopper, the low-k curing processes induce severe damage to the metal lines, leading to the degraded electrical properties. This is confirmed by chemical inspection on the blanketCu films and morphological inspection on patterned structu...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Liping Zhang, Jean-Francois de Marneffe, Alicja Lesniewska, Patrick Verdonck, Nancy Heylen, Gayle Murdoch, Kristof Croes, Juergen Boemmels, Zsolt Tokei, Stefan De Gendt and Mikhail R. Baklanov Source Type: research
Enhancement of magneto-photogalvanic effect in periodic GaAs dot arrays by p-n junctions coupling
To control thesemiconductor device under lowmagnetic field is still a great challenge forsemiconductormagnetoelectronics. In this work, we report the observation of the magneto-photogalvaniceffect in periodicGaAs dot arrays. With an increase inmagnetic field from 0 to 1500 Oe, the photovoltage increases linearly for a wide temperature range from 80 to 430 K. Compared withGaAs without the dot arrays, periodicGaAs dot arrays have a hundredfold increase of the magnetic-field-modulated photovoltage at room temperature. By changing themagnetic field orientation, the angular dependence of photovoltage reveals that the magne...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: J. K. Zhou, T. Wang, W. Wang, S. W. Chen, Y. Cao, H. P. Liu, M. S. Si, C. X. Gao, D. Z. Yang and D. S. Xue Source Type: research
Spin-orbit torques in Ta/TbxCo100-x ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy
We quantified the bulk perpendicularmagnetic anisotropy (PMA) and spin-orbit torques (SOTs) in bilayer Ta/TbxCo100-xferrimagnetic alloyfilms with varying Tb concentration. Thecoercivity increases dramatically with increasing TbxCo100-x thickness and is enhanced by the presence of aTa underlayer. TheTa underlayer simultaneously serves as a source of SOT due to the spin Hall effect, which we show provides an efficient means to manipulate the magnetization in bulk PMAmaterials. It is further shown that the sign of the anomalous Hall voltage is different for rare-earth (RE) and transition-metal (TM) dominated alloy composition...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Kohei Ueda, Maxwell Mann, Chi-Feng Pai, Aik-Jun Tan and Geoffrey S. D. Beach Source Type: research
Spin transport in nanoscale Si-based spin-valve devices
We investigated the spintransport in nano-scalesilicon (Si)-basedspin-valve devices with Feelectrodes, MgO/Ge tunnel barriers, and a 20 nm-long Si channel. We observed a clearspin-valveeffect when amagnetic field was applied in the film plane along and perpendicular to the Si channeltransport direction. Systematic investigations of the bias voltage dependence, temperature dependence, and magnetic-field direction dependence of themagnetoresistance indicate that the observedspin-valveeffect is governed by the spintransport through the nano-scale Si channel. Thespin-valveeffect remains observable up to 200 K. For the de...
Source: Applied Physics Letters - December 5, 2016 Category: Physics Authors: Duong Dinh Hiep, Masaaki Tanaka and Pham Nam Hai Source Type: research
