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samsung electronics faculty summaries and technology abstracts for more information contact sonia kim phd manager for marketing and industry partnerships innovation and new ventures office 1800 sherman ave suite 504 evanston il 60201 main 847 467-2097 direct 847 467-0446 email invo@northwestern.edu or sonia.kim@northwestern.edu 1

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contents telecommunications seng-tiong ho phd 4 electric field sensor with ultra-sensitivity over broad frequency 4 seng-tiong ho phd and tobin marks phd 5 transparent conducting oxide electrodes significantly lowers modular switching voltages 5 organic electro-optic modulators with transparent electrodes device structures 6 mercouri kanatzidis phd 7 nonlinear optic glassy fiber with strong intrinsic second harmonic generation 7 bruce wessels phd 8 batio3 thin film waveguide modulator with an increased electro-optic coefficient and wider bandwidth 8 highly efficient broadband second harmonic generation using batio3 thin film waveguides 9 robert dick phd peter dinda phd and gokhan memik phd 10 indoor positioning using spectral acoustic fingerprinting 11 semiconductors related applications mark hersam phd 12 bridge enhanced nanoscale impedance microscopy 12 atomic force electroluminescence microscopy 13 cryogenic variable temperature scanning tunneling microscope 14 tobin marks phd 15 catalytic synthesis of high energy density nanocomposite dielectric materials 15 nanoscale self-assembled organic dielectrics for ultra-low voltage high-speed electronic devices 16 enhanced performance of blue light emitting polymer diodes via anode modification 17 new hole transport layer materials for polymer light emitting diodes 18 novel tfb:tpdsi2 interfacial layer with improved power conversion efficiency for organic photovoltaic cells 19 seng-tiong ho phd 20 low-voltage organic electro-optic modulators using transparent conducting oxides as electrodes 20 chad mirkin phd 21 on-wire lithography 21 beam pen lithography 22 2

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teri odom phd 23 programmable soft lithography solvent-assisted nanoscale embossing 23 novel techniques for the production of large-area subwavelength hole arrays 24 a compact and portable benchtop photolithography system 25 mesoscale metallic pyramids with nanoscale tips 26 bruce wessels phd 27 thin uniform layer of epitaxial oxide on si substrates for microelectronic and microphotonic devices 27 novel semiconductor magnetodiodes for use in magnetic field sensors 28 medical diagnostic devices konrad kording phd 29 using a mobile phone as a diagnostic tool for clinical rehabilitation 29 vadim backman phd 30 inverse scattering optical coherence tomography 30 andrew larson phd and reed omary md 31 methods and composition for applications involving magnetic sutures wires clips and staples 31 graphene mark hersam phd 32 preparation of robust molecularly pristine self-assembled organic monolayers of graphene 32 highly concentrated graphene solutions via iterative solvent exchange 33 centrifugal processing of carbon nanotubes and graphene oxide for cement composites 34 jiaxing huang phd 35 flash reduction of graphic oxide to graphene 35 two dimensional assembly of graphite oxide single layers and applications of the same 36 high-throughput imaging of graphene-based sheets by fluorescence quenching microscopy 37 compression and aggregation-resistant particles of crumpled sheets 38 sonbinh nguyen phd 39 graphene oxide paper with high pliability and resiliency 39 conducting and transparent graphene-containing thin silica films 40 vaccum-assisted self-assembly for the creation of layered nanocomposites 41 3

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telecommunications seng-tiong ho phd professor of electronical and computer engineering the ho lab is focused on the following areas of research 1 nanophotonics nanoscale lasers microring resonators photonic bandgap structures and wavelength mux/demux 2 optical communications devices for dwdm network applications 3 photonics integration high-density integration of iii-v optoelectronic and photonic devices 4 organic photonics self-assembly organic eo modulators and organic light-emitting devices 5 photonic materials research thin-film electro-optic modulators transparent conducting oxides 6 heterogeneous photonics integrated photonic devices utilizing crossplatform technologies such as optical mems 7 ultrafast nonlinear photonics ultrafast low-power alloptical wavelength converters routers switches and logic gates 8 micro-optics micro-optical lenses and silicon optical bench 9 device simulation simulation of optoelectronic and all-optical devices and 10 quantum optics generation of quantum states of light electric field sensor with ultra-sensitivity over broad frequency nu2010-149 inventors seng-tiong ho fei yi abstract northwestern researchers have designed an ultra-sensitive electric field detector e-fed over large frequency ranges despite the level of difficulty in achieving high sensitivity over a broad frequency range the investigators amplify the sensitivity to electric field strength by 150 times using two unique features they apply a microantenna to the electro-optic material and also use a transparent conducting oxide tco enhancement directly across the electro-optic material to conduct voltage furthermore they utilize multi-pass and/or resonator structures to increase sensitivity another ten-fold and an optical-carrier-reduction scheme using an optical interference technique with matched arms in total the multiple factors together offer a 100,000 times increase in 1/2 sensitivity compared to current eo approaches that can only detect tens of mv/mhz applications optical communications rf photonics optical interconnect advantages increased sensitivity to electric field strength wider bandwidth compact and power efficient ip status a patent application has been filed 4

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tobin marks phd professor of chemistry and materials science and engineering prof marks lab is interested in synthetic organo-f-element and early-transition metal organometallic chemistry polymer chemistry materials chemistry homogeneous and heterogeneous catalysis moleculebased photonic materials superconductivity metal-organic chemical vapor deposition and biological aspects of transition metal chemistry transparent conducting oxide electrodes significantly lowers modular switching voltages nu 2003-080 inventors seng-tiong ho jing ma tobin marks guoyang xu despite great efforts to gain lower switching voltages in modulators with higher electro-optic eo coefficient materials and new device configurations optimal properties have not yet been achieved northwestern researchers have employed transparent conducting oxides tco as device electrode materials which provide low optical loss and adjustable conductivity compared to metallic electrodes by inserting the thin film nonlinear eo materiasl directly between the tco electrodes additional voltage drop from the top and bottom claddings is eliminated and the electrical modulation field of the eo material is increased overall these changes result in a significant reduction in modular switching voltage resulting in 3-4 times greater electrical field and 3-4 times lower switching voltage compared to conventional modulators application high speed optoelectronics and photonics advantages signficantly lower switching voltages significant increases in modulation frequency ip status issued us patent no 7,835,597 5

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organic electro-optic modulators with transparent electrodes device structures nu 2008-155 inventors seng-tiong ho tobin marks fei yi abstract northwestern researchers have developed a novel construction for electro-optic eo modulators and related devices eo optical intensity modulators are widely used in optical fiber communications to modulate light from semiconductor lasers to produce the required optical pulses carrying digital data for transmission at high modulation rates above 10 gbits/sec a frequency chirped pulse change in the lasing frequency at the leading and trailing edges of the pulse will be rapidly broadened in width after propagating through a long length of optical fiber causing serious degradation in the signal integrity thus external optical intensity modulators are needed for long distance optical communications at bit rates at or above 10 gbits/sec current commercially-available high-speed eo optical intensity modulators are based on lithium niobate crystals and require about 0.5 w of electrical power which is high and quite inefficient in terms of electrical-to-optical signal-power conversion for typical semiconductor laser power while there is much interest in reducing the modulator driving voltage current modulator designs and component materials tend to limit further advances in performance the present invention provides electro-optic modulators and related devices that address these shortcomings the researchers have designed a modulator that utilizes organic electro-optic materials with exceptionally high eo coefficients by incorporating transparent conducting oxide electrode bridge components and horizontal optical mode confinement with optimized electrical and optical characteristics it exhibits lower switching power and a compact device structure this combination of design and materials promise significant advancement for long distance optical communications at 10 gbits/sec bit rates and above applications long distance optical communications advantages lower switching voltage improved performance compact structure ip status patent applications have been filed 6

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mercouri kanatzidis phd professor of chemistry the kanatzidis laboratory develops new materials that enable record-breaking high performance advances in a number of technological areas a porous materials for the specific capture and removal of toxic heavy metals clean up and radioactive ions decontamination b porous materials for the specific capture and recovery of precious metals c thermoelectric materials for the conversion of heat to electricity d materials for the detection of hard radiation gamma and x-ray e materials for novel highly efficient inexpensive solar cells nonlinear optic glassy fiber with strong intrinsic second harmonic generation nu 2007-166 and 2009-048 inventors in chung mercouri kanatzidis abstract northwestern researchers have developed nonlinear optic nlo glassy fiber and thin film technology that effectively produces coherent light at frequencies where lasers perform poorly or are unavailable while most shg materials are oxide compounds they are inefficient in the ir region because of issues with absorption this new method is not only inexpensive and convenient but also produces optical glassy fibers exhibiting strong intrinsic nlo second harmonic generation shg using non-centrosymmetric chalcophosphate materials the nlo films can be deposited conveniently from solution from the melt of alkali metal selenophosphate ternary compounds at temperatures between the melting and vitrification points a high quality optical glassy fiber can be easily drawn out in multi meters in length and a few to hundred microns in thickness the optical glassy fibers and thin films outperformed any known nlo materials in shg susceptibility and exhibited strong waveguided second harmonic generation response along the fiber the nonlinear optical response was present without the application of electric fields poling to the fibers and successfully generated a frequency mixing signal of difference frequency generation dfg continuously in a wide range of visible/ir region applications · secure communication textual and/or graphical information storage for a prescribed period of time advantages · inexpensive and convenient · strong intrinsic shg using non-centrosymmetric chalcophosphate materials · good wave-mixing performance without the need for poling · function in waveguide mode in the visible and the near ir region · extremely flexible fibers · solution processable films ip status patent applications have been filed 7

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bruce wessels phd professor of chemistry and materials science and engineering dr wessels laboratory develops thin films and nanostructures for electronic magnetic and photonic materials applications with emphasis on semiconductor and ferroic oxide thin films metal-organic vapor phase epitaxy techniques have been developed and applied to both narrow band gap and wide band gap compound semiconductors including inmnsb inmnas and ingan alloy semiconductors their electronic optical and magnetic properties are characterized using a variety of techniques including photoluminescence spectroscopy magneto-optic kerr effect and magnetoresistance measurements ferromagnetic inmnas is being developed as a spintronic material for nanoelectronics heterojunction spintronic devices are fabricated and their transport properties measured batio3 thin film waveguide modulator with an increased electro-optic coefficient and wider bandwidth nu 2004-060 inventors anthony meier pingsheng tang david towner bruce wessels abstract northwestern researchers have developed a low-voltage wide bandwidth strip-loaded barium titanate batio3 thin film electro-optic eo amplitude modulator for use in high-speed optical communication networks they have demonstrated broadband modulation out to 40 ghz at which value low power eo waveguide modulators may have high eo coefficients eo waveguide modulators are essential for high speed and wide bandwidth optical communication systems currently lithium niobate is widely used for low loss low drive voltage and high-speed modulators due to its high eo coefficient and excellent optical transparency however batio 3 has an eo coefficient that is forty times greater and promises improved performance while employing smaller devices nevertheless the large bulk dielectric constant of batio3 limits its high modulation bandwidth operation to address this limitation batio3 can be combined with mgo as a composite which lowers the effective microwave index and improves velocity matching between the microwave and optical waves furthermore batio 3 can be integrated with silicon substrates using a thin film mgo buffer layer allowing integration on a single multicomponent chip with reduced packaging costs applications · high-speed optical communication networks advantages · compatible with silicon substrates · significantly increased eo coefficient · decreased effective microwave index · improved velocity matching between microwave and optical waves · wide bandwidth over 40 ghz ip status issued u.s patent no 7,224,878 8

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highly efficient broadband second harmonic generation using batio 3 thin film waveguides nu 2008-009 inventors pao tai lin bruce wessels abstract northwestern researchers have developed highly efficient broadband second harmonic generation shg in the visible spectrum which promises improved broadband sources for optical communication devices including waveguides filters switches and photonic circuits while shg can produce light over a wide spectral range efficient shg requires a material with a large second order nonlinear optical coefficient such as ferroelectric oxides batio3 bto has also been shown to have excellent nonlinear optical properties this technology utilizes polydomain epitaxial bto to fabricate thin film waveguides which offers potential integration of optical components in si semiconductors this novel bto waveguide structure minimizes the critical phase matching requirement for broadband shg and offers a wider range of wavelengths using typical periodic structures shg of light using bto thin films has previously been demonstrated in the transition mode with pump beam normal to the film surface however the short light interaction length offered low conversion efficiency in this mode utilization of this planar bto waveguide permits light to propagate within the thin film plane increasing the nonlinear optical interaction length and overcomes this limitation applications optical communications waveguides filters switches and photonic circuits with a broadband optical response advantages generation of visible light from 530 to 700 nm with high intensity higher shg conversion efficiency no requirements for critical phase matching wide range of available wavelengths ip status issued us patent no 7,898,730 9

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peter dinda phd professor of electrical engineering and computer science at the highest level of abstraction the goal of prof dinda s research is to learn how to best distribute computing resources to interactive applications more specifically their group focuses on how to build adaptive distributed interactive applications effectively better understanding the demand for resources and the supply for resources in these applications vary over time and optimizing to use the adaptation mechanisms exposed by an application to match its resource demand with resource supply gokhan memik phd,associate professor of electrical engineering and computer science prof memik s research focuses on computer architecture microarchitecture and computer systems specifically his group works on understanding the effects of applications users and underlying technologies on architectures and vice versa these efforts include incorporating holistic effects into architecture design process for example investigating the impact of architectures on users utilizing biological information to make architectural decisions estimating profitability of a design application-specific processors for example architectures and compilers for networking security and data mining and physical-aware architectures architectures for minimizing the power consumption reducing operating temperatures and mitigating the effects of process variations 10

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indoor positioning using spectral acoustic fingerprinting nu 2011-036 inventors robert dick peter dinda gokhan memik stephen tarzia abstract wi-fi and cellular base station based technologies are often applied to the problem of indoor localization when gps sensing is not possible however these technologies suffer from localization difficulties due to temporal instabilities diurnal changes in the physical environment and interference from other electronic devices and insufficient spatial densities researchers from northwestern university and the university of michigan have developed a technology for indoor localization based on a new ambient sound fingerprint called the acoustic background spectrum the frequency-domain-based fingerprints are compact easily computed robust to transient sounds and highly distinctive abs can also be used in conjunction with wi-fi based techniques and improve upon the performance of the latter 69 accuracy with abs vs 30 without abs can also distinguish between adjacent rooms with 92 accuracy applications location-based services including social-media check-ins business restaurant and entertainment recommendations and targeted advertising and retail discounts enhanced visitor experience e.g malls museums and transportation hubs fraud prevention under cellphone-based payment regimes advantages light-weight low-cost robust to transient sounds highly distinctive fingerprints higher accuracy of indoor location tracking than extant technologies automated tracking of potential customers for location-based services ip status a patent application has been filed 11

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semiconductors related applications mark hersam phd professor in materials science and engineering the hersam laboratory develops chemically refined nanomaterials with unprecedented control over structure properties and surface chemistry of particular interest are carbon-based nanomaterials including carbon nanotubes and graphene due to their diverse range of applications in electronics optoelectronics photovoltaics batteries biomedical imaging and drug delivery in addition to synthesis and fabrication of nanomaterials and devices the hersam laboratory also develops scanning probe characterization methods with spatial resolution down to the atomic scale specific examples include cryogenic variable temperature ultra-high vacuum scanning tunneling microscopy nanoscale impedance microscopy atomic force electroluminescence microscopy and atomic force photovoltaic microscopy bridge enhanced nanoscale impedance microscopy be-nim nu 2005-060 inventors mark hersam liam pingree abstract northwestern scientists have developed a conductive atomic force microscopy cafm adjunct that is capable of quantitatively measuring the magnitude and phase of alternating current flow through the tip/sample junction with a five order of magnitude improvement in sensitivity this technology called bridge enhanced nanoscale impedance microscopy be-nim offers significant improvement in sensitivity and spatial resolution for the study of electronic behavior in nanomaterials and biological samples while macroscopic impedance spectroscopy techniques have been employed to characterize alternating current charge transport for a variety of materials systems and devices they only reveal an ensemble average of the underlying contributions of individual pathways defects film thickness variations electrochemical reactions and failure mechanisms scanning probe impedance measurement techniques based on the conductive atomic force microscope cafm has enabled probing current flow and resistivity variations on conductive surfaces with nanoscale spatial resolution however fringe capacitance 1-100 picof between the sample and the probe imposes a serious detection limit in an effort to improve the sensitivity of nanoscale impedance microscopy be-nim offers a variable resistor/capacitor rc bridge circuit to cancel the spurious contribution to the ac current flow caused by fringe capacitance this addition significantly improves the detection limit of nim by at least five orders of magnitude enabling the detection of impedance values that are typical for many nanostructures nano-electrochemical cells and biological systems applications study of electrical properties of nanomaterials and biological samples advantages greater spatial resolution greater sensitivity ip status issued us patent no 7,705,617 12

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atomic force electroluminescence microscopy nu 2004-050 inventors mark hersam liam pingree abstract northwestern scientists have developed a new atomic force electroluminescence microscopy afem technology that is capable of gathering simultaneous topographical current and electroluminescence information through a commercially available conductive afm tip this technology characterizes individual bottom-emitting opto-electronic devices such as light-emitting diodes and electroluminescent devices at a resolution of 10 nm it has a particularly significant impact on the application of organic light-emitting diodes oleds in inexpensive large area high brightness and flexible color displays spatial mapping and correlation of topology current and electroluminescence characteristics of operating oleds are critical to achieve oled miniaturization for high density display by incorporating collection optics and photon detectors afem enables the resulting electroluminescence to be spatially correlated with tip position and nanometer scale mapping applications high density flexible color displays characterization of electroluminescence from semiconducting nanowires nanotubes and submicron optoelectronic devices advantages advanced operation increased light sensitivity greater resolution electroluminescence with nanometer spatial resolution ability to measure current input and emission spectroscopy publications pingree lsc hersam mc kern mm scott bj and marks tj 2004 spatially-resolved electroluminescence of operating organic light-emitting diodes using conductive atomic force microscopy applied physics letters 85 344-346 doi:10.1063/1.1765206 ip status issued us patent no 7,358,490 13

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cryogenic variable temperature scanning tunneling microscope nu 2004-108 inventors edward foley mark hersam abstract northwestern researchers have developed and designed a robust instrument that is capable of high atomic resolution at 8.2 to 300k critical for single molecule surface studies an essential design problem with current scanning tunneling microscopy is inadequate coupling to the cryogen to maintain a stable low temperature while being sufficiently decoupled from any source of environmental vibration this instrument utilizes the ease of use and thermal stability of a dual thermal shield continuous flow cryostat cooling system and the atomic resolution fcl capability of the stm scanner and controls present innovations include a shapal-m® aluminum nitride ceramic used for heat-sinking electrical isolation a beryllium copper sample holder to improve platform durability and thermal properties and use of titanium nitride coated platform rails to enhance inertial translation of the sample holder at cryogenic temperatures by varying the cryogen flow rate and actively heating the thermal shields the stm may be operated at any temperature from 8.2 to 300 k the design allows for dosing of samples with an ex situ source through a variable leak valve or with an in situ evaporation/sublimation module the system affords excellent drift stability 0.008 a/min tip-sample spacing 8.2 k which was unchanged at sustained background acoustic noise levels up to 68 db in addition shuttered sapphire windows allow direct optical access of the tip-sample junction at cryogenic temperatures atomic resolution fcl on hydrogen passivated si100 surfaces and cryogenic stm studies of individual molecules on degenerately doped silicon surfaces at cryogenic temperatures have been demonstrated with the device applications atomic microscopy at cryogenic temperatures advantages atomic resolution at cryogenic temperatures excellent thermal insulation superior drift stability stable vibrational operation direct optical access to the tip-sample interface and direct line-of-sight dosing of the sample publications foley et yoder nl guisinger np and hersam mc 2004 cryogenic variable temperature ultrahigh vacuum scanning tunneling microscope for single molecule studies on silicon surfaces review of scientific instruments 75 5280-5287 ip status issued us patent no 7,414,250 14

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tobin marks phd professor of chemistry and materials science and engineering prof marks lab is interested in synthetic organo-f-element and early-transition metal organometallic chemistry polymer chemistry materials chemistry homogeneous and heterogeneous catalysis moleculebased photonic materials superconductivity metal-organic chemical vapor deposition and biological aspects of transition metal chemistry catalytic synthesis of high energy density nanocomposite dielectric materials nu 2006-136 inventors sara dibenedetto neng guo mike lanagan tobin marks abstract future pulsed-power capacitors will require dielectric materials having very large energy densities with operating voltages 10 kv the operating characteristics of current state-of-the-art pulsed-power capacitors which utilize either ceramics or polymers as dielectric materials fall significantly short of this goal to address this researchers at northwestern university have developed nanocomposites that combine inorganic constituents and polymer matrices these new materials are formed via in situ propylene polymerization using a metallocene catalyst supported on ferroelectric oxide nanoparticles physical characterization has established that the nanoparticles are uniformly dispersed in a highly isotactic polypropylene matrix importantly these new nanocomposites have proven to be excellent insulators with energy densities comparable or exceeding values reported for ceramic polymer and composite dielectrics these exciting new nanocomposites promise a new family of dielectric materials for future high energy capacitor applications application high energy storage in capacitor and insulator applications advantages combination of inorganic and polymeric materials energy densities exceed current ceramic or polymer-based insulators significant potential for future high-energy capacitor applications publications guo n dibenedetto sa kwon dk wang l russell mt lanagan mt facchetti a marks tj 2007 supported metallocene catalysis for in situ synthesis of high energy density metal oxide nanocomposites journal of the american chemical society 129 766-767 guo n dibenedetto sa tewari p lanagan mt ratner ma marks tj 2010 nanoparticle size shape and interfacial effects on leakage current density permittivity and breakdown strength of metal oxide polyolefin nanocomposites experiment and theory chemistry of materials 22 1567-1578 li z fredin la tewari p dibenedetto sa lanagan mt ratner ma marks tj 2010 in situ catalytic encapsulation of core-shell nanoparticles having variable shell thickness dielectric and energy storage properties of highpermittivity metal oxide nanocomposites chemistry of materials 22 5154-5164 ip status patent applications have been filed 15

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