Engineering Commons^™

Generation Of Dna Oligomers With Similar Chemical Kinetics Via In-Silico Optimization, Michael Tobiason, Bernard Yurke, William L. Hughes

Electrical and Computer Engineering Faculty Publications and Presentations

Networks of interacting DNA oligomers are useful for applications such as biomarker detection, targeted drug delivery, information storage, and photonic information processing. However, differences in the chemical kinetics of hybridization reactions, referred to as kinetic dispersion, can be problematic for some applications. Here, it is found that limiting unnecessary stretches of Watson-Crick base pairing, referred to as unnecessary duplexes, can yield exceptionally low kinetic dispersions. Hybridization kinetics can be affected by unnecessary intra-oligomer duplexes containing only 2 base-pairs, and such duplexes explain up to 94% of previously reported kinetic dispersion. As a general design rule, it is recommended that unnecessary …

Strategies For Controlling The Spatial Orientation Of Single Molecules Tethered On Dna Origami Templates Physisorbed On Glass Substrates: Intercalation And Stretching, Keitel Cervantes-Salguero, Austin Biaggne, John M. Youngsman, Brett M. Ward, Young C. Kim, Lan Li, John A. Hall, William B. Knowlton, Elton Graugnard, Wan Kuang

Electrical and Computer Engineering Faculty Publications and Presentations

Nanoarchitectural control of matter is crucial for next-generation technologies. DNA origami templates are harnessed to accurately position single molecules; however, direct single molecule evidence is lacking regarding how well DNA origami can control the orientation of such molecules in three-dimensional space, as well as the factors affecting control. Here, we present two strategies for controlling the polar (θ) and in-plane azimuthal (ϕ) angular orientations of cyanine Cy5 single molecules tethered on rationally-designed DNA origami templates that are physically adsorbed (physisorbed) on glass substrates. By using dipolar imaging to evaluate Cy5′s orientation and super-resolution microscopy, the absolute …

Exciton Delocalization And Scaffold Stability In Bridged Nucleotide-Substituted, Dna Duplex-Templated Cyanine Aggregates, Simon K. Roy, Olga A. Mass, Donald L. Kellis, Christopher K. Wilson, John A. Hall, Bernard Yurke, William B. Knowlton

Electrical and Computer Engineering Faculty Publications and Presentations

Molecular excitons play a foundational role in chromophore aggregates found in light-harvesting systems and offer potential applications in engineered excitonic systems. Controlled aggregation of chromophores to promote exciton delocalization has been achieved by covalently tethering chromophores to deoxyribonucleic acid (DNA) scaffolds. Although many studies have documented changes in the optical properties of chromophores upon aggregation using DNA scaffolds, more limited work has investigated how structural modifications of DNA via bridged nucleotides and chromophore covalent attachment impact scaffold stability as well as the configuration and optical behavior of attached aggregates. Here we investigated the impact of two types of bridged nucleotides, …

Demonstration Of Three True Random Number Generator Circuits Using Memristor Created Entropy And Commercial Off-The-Shelf Components, Scott Stoller, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

In this work, we build and test three memristor-based true random number generator (TRNG) circuits: two previously presented in the literature and one which is our own design. The functionality of each circuit is assessed using the National Institute of Standards and Technology (NIST) Statistical Test Suite (STS). The TRNG circuits were built using commercially available off-the-shelf parts, including the memristor. The results of this work confirm the usefulness of memristors for successful implementation of TRNG circuits, as well as the ease with which a TRNG can be built using simple circuit designs and off-the-shelf breadboard circuit components.

Comparison Of The Electrical Response Of Cu And Ag Ion-Conducting Sdc Memristors Over The Temperature Range 6 K To 300 K, Kolton Drake, Tonglin Lu, Md. Kamrul H. Majumdar, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

Electrical performance of self-directed channel (SDC) ion-conducting memristors which use Ag and Cu as the mobile ion source are compared over the temperature range of 6 K to 300 K. The Cu-based SDC memristors operate at temperatures as low as 6 K, whereas Ag-based SDC memristors are damaged if operated below 125 K. It is also observed that Cu reversibly diffuses into the active Ge₂Se₃ layer during normal device shelf-life, thus changing the state of a Cu-based memristor over time. This was not observed for the Ag-based SDC devices. The response of each device type to sinusoidal …

Development And Assessment Of A Combined Reu/Ret Program In Materials Science, Noah Salzman, Rick Ubic

Electrical and Computer Engineering Faculty Publications and Presentations

In this paper we present an evaluation and lessons learned from a joint Research Experience for Undergraduates (REU) and Research Experience for Teachers (RET) program focused on energy and sustainability topics within a Materials Science and Engineering program at a public university. This program brought eleven undergraduate science and engineering students with diverse educational and institutional backgrounds and four local middle and high school teachers on campus for an 8-week research experience working in established lab groups at the university.

Using the Qualtrics online survey software, we conducted pre-experience and post-experience surveys of the participants to assess the effects of …

Self-Directed Channel Memristor For High Temperature Operation, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

Ion-conducting memristors comprised of the layered chalcogenide materials Ge₂Se₃/SnSe/Ag are described. The memristor, termed a self-directed channel (SDC) device, can be classified as a generic memristor and can tolerate continuous high temperature operation (at least 150 °C). Unlike other chalcogenide-based ion conducting device types, the SDC device does not require complicated fabrication steps, such as photodoping or thermal annealing, making these devices faster and more reliable to fabricate. Device pulsed response shows fast state switching in the 10⁻⁹ s range. Device cycling at both room temperature and 140 °C show write endurance of at least …

Pulse Shape And Timing Dependence On The Spike-Timing Dependent Plasticity Response Of Ion-Conducting Memristors As Synapses, Kris A. Campbell, Kolton T. Drake, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

Ion-conducting memristors comprised of the layered materials Ge₂Se₃/SnSe/Ag are promising candidates for neuromorphic computing applications. Here, the spike-timing dependent plasticity (STDP) application is demonstrated for the first time with a single memristor type operating as a synapse over a timescale of 10 orders of magnitude, from nanoseconds through seconds. This large dynamic range allows the memristors to be useful in applications that require slow biological times, as well as fast times such as needed in neuromorphic computing, thus allowing multiple functions in one design for one memristor type—a “one size fits all” approach. This work also …

Evolution Of A First-Year Engineering Course, Noah Salzman, Janet Callahan, Gary Leroy Hunt, Carol Sevier, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

The first-year engineering course at Boise State University has evolved significantly over the past decade as a result of continuous improvement with a particular focus on student retention. The course was originally created in 1999-2001 as an “Introduction to Engineering” course in order to recruit students to one of the fields of engineering, by introducing those fields of engineering as topics across the semester. Over the first ten years, the course continued that introductory-to-field focus while also introducing a significant design element solving openended engineering problems. As a result of a five-year grant aimed toward improving first-year retention, the first-year …

Energy-Efficient Stdp-Based Learning Circuits With Memristor Synapses, Xinyu Wu, Vishal Saxena, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

It is now accepted that the traditional von Neumann architecture, with processor and memory separation, is ill suited to process parallel data streams which a mammalian brain can efficiently handle. Moreover, researchers now envision computing architectures which enable cognitive processing of massive amounts of data by identifying spatio-temporal relationships in real-time and solving complex pattern recognition problems. Memristor cross-point arrays, integrated with standard CMOS technology, are expected to result in massively parallel and low-power Neuromorphic computing architectures. Recently, significant progress has been made in spiking neural networks (SNN) which emulate data processing in the cortical brain. These architectures comprise of …

Multiscaffold Dna Origami Nanoparticle Waveguides, William P. Klein, Charles N. Schmidt, Blake Rapp, Sadao Takabayashi, William B. Knowlton, Jeunghoon Lee, Bernard Yurke, William L. Hughes, Elton Graugnard, Wan Kuang

Electrical and Computer Engineering Faculty Publications and Presentations

DNA origami templated self-assembly has shown its potential in creating rationally designed nanophotonic devices in a parallel and repeatable manner. In this investigation, we employ a multiscaffold DNA origami approach to fabricate linear waveguides of 10 nm diameter gold nanoparticles. This approach provides independent control over nanoparticle separation and spatial arrangement. The waveguides were characterized using atomic force microscopy and far-field polarization spectroscopy. This work provides a path toward large-scale plasmonic circuitry.

Reconfigurable Threshold Logic Gates Using Memristive Devices, Adrian Rothenbuhler, Thanh Tran, Elisa H. Barney Smith, Vishal Saxena, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

We present our design exploration of reconfigurable Threshold Logic Gates (TLG) implemented using silver–chalcogenide memristive devices combined with CMOS circuits. Results from simulations and physical circuits are shown. A variety of linearly separable logic functions including AND, OR, NAND, NOR have been realized in discrete hardware using a single-layer TLG. The functionality can be changed between these operations by reprogramming the resistance of the memristive devices.

Electron Self-Trapping In Ge2 Se3 And Its Role In Ag And Sn Incorporation, Arthur H. Edwards, Kristy A. Campbell, Andrew C. Pineda

Electrical and Computer Engineering Faculty Publications and Presentations

We present a set of density functional theory (DFT) calculations on the electronic structure of Ag and Sn in Ge₂ Se₃ in a periodic model. We show that electron self-trapping is a persistent feature in the presence of many defects. Ag and Sn autoionize upon entering Ge₂ Se₃ becoming Ag₊ and Sn₂₊ , respectively, and the freed electrons self trap at the lowest energy site. Both Ag and Sn can substitute for Ge, and we present formation energies as a function of Fermi level that show that Sn can substantially alter the incorporation of …

Application Of Image Processing To Track Twin Boundary Motion In Magnetic Shape Memory Alloys, Adrian Rothenbuhler, Elisa Barney Smith, Peter Müllner

Electrical and Computer Engineering Faculty Publications and Presentations

Materials scientists make use of image processing tools more and more as technology advances and the data volume that needs to be analyzed increases. We propose a method to optically measure magnetic eld induced strain (MFIS) as well as twin boundary movement in Ni₂MnGa single crystal shape memory alloys to facilitate spatially resolved tracking of deformation. Current magneto-mechanical experiments used to measure MFIS can measure strain only in one direction and do not provide information about the movement of individual twin boundaries. A sequence of images captured from a high resolution camera is analyzed by a boundary detection …

Cavity Resonant Mode In A Metal Film Perforated With Two-Dimensional Triangular Lattice Hole Arrays, Wan Kuang, Alex English, William B. Knowlton, Jeunghoon Lee, William L. Hughes, Bernard Yurke

Electrical and Computer Engineering Faculty Publications and Presentations

The transmission property of metallic films with two-dimensional hole arrays is studied experimentally and numerically. For a triangular lattice subwavelength hole array in a 150 nm thick Ag film, both cavity resonance and planar surface modes are identified as the sources of enhanced optical transmissions. Semi-analytical models are developed for calculating the dispersion relation of the cavity resonant mode. They agree well with the experimental results and full-wave numerical calculations. Strong interaction between the cavity resonant mode and surface modes is also observed.

Silver Chalcogenide Based Memristor Devices, Antonio S. Oblea, Achyut Timilsina, David Moore, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

We have fabricated two-terminal chalcogenide-based devices containing Ge₂Se₃ and Ag that function as memristors. These devices have been electrically characterized at room temperature using quasi-static DC methods, AC sinusoidal methods, and AC pulse testing methods. In all cases, the devices exhibit memristive behavior.

Compact Method For Modeling And Simulation Of Memristor Devices: Ion Conductor Chalcogenide-Based Memristor Devices, Kristy A. Campbell, Antonio Oblea, Achyut Timilsina

Electrical and Computer Engineering Faculty Publications and Presentations

A compact model and simulation methodology for chalcogenide based memristor devices is proposed. From a microprocessor design view point, it is important to be able to simulate large numbers of devices within the integrated circuit architecture in order to speed up reliably the development process. Ideally, device models would accurately describe the characteristic device behavior and would be represented by single-valued equations without requiring the need for recursive or numerically intensive solutions. With this in mind, we have developed an empirical chalcogenide compact memristor model that accurately describes all regions of operations of memristor devices employing single-valued equations.

Atomic Force Microscopy Of Dna Self-Assembled Nanostructures For Device Applications, Hieu Bui, Craig Onodera, Bernard Yurke, Elton Graugnard, Wan Kuang, Jeunghoon Lee, William B. Knowlton, William L. Hughes

Electrical and Computer Engineering Faculty Publications and Presentations

DNA nanotechnology, which relies on Watson-Crick hybridization, is a versatile selfassembly process whereby a variety of complex nanostructures can be fabricated with sublithographic features.[1] Adopting this technology, 1012 identical devices can be synthesized to have hundreds of components with 1nm resolution. Example nanostructures include: 1) DNA motifs [2], 2) two-dimensional DNA crystals [3], and DNA origami [4]. Currently, this technology is being adopted towards electronic, optical, and opto-electronic devices.[5]

Chip-Scale Nanophotonic Chemical And Biological Sensors Using Cmos Process, Lincoln Bollschweiler, Alex English, R. Jacob Baker, Wan Kuang, Zi-Chang Chang, Ming-Hsiung Shih, William Knowlton

Electrical and Computer Engineering Faculty Publications and Presentations

A monolithic integrated chip-scale surface plasmon resonance (SPR) sensor is demonstrated. The device consists of a pn photodiode covered with a periodic modified thin metal film whose lattice constant is on the order of the wavelength of light. The device performs real-time measurement of resonant wavelengths of enhanced optical transmission due to surface plasmon resonance, which are influenced by the presence of chemical or biological materials at the device’s surface.

Temperature (5.6-300k) Dependence Comparison Of Carrier Transport Mechanisms In Hfo2/Sio2 And Sio2 Mos Gate Stacks, Richard G. Southwick Iii, Justin Reed, Christopher Buu, Hieu Bui, Ross Butler, G. Bersuker, William B. Knowlton

Electrical and Computer Engineering Faculty Publications and Presentations

Temperature dependent measurements have been used to examine transport mechanisms and energy band structure in MOS devices. In this study, a comparison between high-k HfO₂ dielectrics and conventional SiO₂ dielectrics is made to investigate dielectric specific thermally activated mechanisms. Temperature dependent measurements on large area n/pMOSFETs composed of SiO₂ and HfO₂/SiO₂ gate dielectrics were performed from 5.6 K to 300 K. A large increase in the gate leakage current is observed at the formation of the minority carrier channel. The data indicate that gate leakage current prior to the formation of the minority channel …

A New Approach To The Design, Fabrication, And Testing Of Chalcogenide-Based Multi-State Phase-Change Nonvolatile Memory, H. K. Ande, P. Busa, M. Balasubramanian, Kristy A. Campbell, R. Jacob Baker

Electrical and Computer Engineering Faculty Publications and Presentations

A new approach to developing, fabricating, and testing chalcogenide-based multi-state phase-change nonvolatile memory (NVM) is presented. A test chip is fabricated through the MOSIS service. Then post processing, in the Boise State University lab, is performed on the chip to add the chalcogenide material that forms the NVM. Each memory bit consists of an NMOS access transistor and the chalcogenide material placed between the metal3 of the test chip, connected to the access device, and a common, to all memory bits, electrode. This paper describes the design of the memory bit and of the test structures used for reliability and …

Integrating Through-Wafer Interconnects With Active Devices And Circuits, Jim Jozwiak, Richard G. Southwick Iii, Vaughn N. Johnson, William B. Knowlton, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Through wafer interconnects (TWIs) enable vertical stacking of integrated circuit chips in a single package. A complete process to fabricate TWIs has been developed and demonstrated using blank test wafers. The next step in integrating this technology into 3D microelectronic packaging is the demonstration of TWIs on wafers with preexisting microcircuitry. The circuitry must be electrically accessible from the backside of the wafer utilizing the TWIs; the electrical performance of the circuitry must be unchanged as a result of the TWI processing; and the processing must be as cost effective as possible. With these three goals in mind, several options …

Thermo-Mechanical Characterization Of Copper Through-Wafer Interconnects, Peter A. Miranda, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Copper through wafer interconnects (TWIs) have become a viable solution to providing interconnectivity between stacked die. In a world where minimizing chip real estate while increasing functionality is the goal for further miniaturization of electronics, TWIs hold a key role as new packaging schemes become critical for overall higher density. Little is known, however, about the impacts of mismatched coefficients of thermal expansion (CTEs) inherent to the materials used in their construction. CTE differences, if left unresolved, can pose reliability issues during TWI operation. This research focuses on providing insight into the stress levels experienced by TWI materials through finite …

Novel Slurry Solutions For Thick Cu Cmp, Peter A. Miranda, Jerome A. Imonigie, Aaron L. Erbe, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Electro-plating methods currently used to deposit Cu in through-wafer interconnect applications result in the formation of a thick Cu layer with large amounts of topographical variation. In this paper, alternative methods for thick Cu removal are investigated using a two-step slurry CMP approach.

Interaction Effects Of Slurry Chemistry On Chemical Mechanical Planarization Of Electroplated Copper, Peter A. Miranda, Jerome A. Imonigie, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Recent studies have been conducted investigating the effects of slurry chemistry on the copper CMP process. Slurry pH and hydrogen peroxide concentration are two important variables that must be carefully formulated in order to achieve desired removal rates and uniformity. In applications such as throughwafer vertical interconnects, slurry chemistry effects must be thoroughly understood when copper plating thicknesses can measure up to 20 microns thick. The species of copper present on the surface of the wafer can be controlled through formulation of the slurry chemistry resulting in minimizing non-uniformity while aggressively removing copper. Using a design of experiments (DOE) approach, …