Jong-Souk Yeo

Review Paper: A critical review of the present and future prospects for electronic paper

Abstract— The commercial success of monochrome electronic paper (e-Paper) is now propelling the development of next-generation flexible, video, and color e-Paper products. Unlike the early battles in the 1980s and 1990s between transmissive and emissive display technologies, there is a extraordinary diversity of technologies vying to become the next generation of e-Paper. A critical review of all major e-Paper technologies, including a technical breakdown of the performance limitations based on device physics and commentary on possible future breakthroughs, is presented. In addition, the visual requirements for color e-Paper are provided and compared to standards used in conventional print. It is concluded that researchers have much work remaining in order to bridge the significant gap between reflective electronic displays and print-on-paper.

A High-Speed Optical Multi-Drop Bus for Computer Interconnections

Buses have historically provided a flexible communications structure in computer systems. However, signal integrity constraints of high-speed electronics have made multi-drop electrical busses infeasible. Instead, we propose an optical data bus for computer interconnections. It has two sets of optical waveguides, one as a fan-out and the other as a fan-in, that are used to interconnect different modules attached to the bus. A master module transmits optical signals which are received by all the slave modules attached to the bus. Each slave module in turn sends data back on the bus to the master module. Arrays of lasers, photodetectors, waveguides, microlenses, beamsplitters and Tx/Rx integrated circuits are used to realize the optical data bus. With 1 mW of laser power, we are able to interconnect 8 different modules at 10 Gb/s per channel. An aggregate bandwidth of over 25 GB/s is achievable with 10 bit wide signaling paths.

69.4: Novel Flexible Reflective Color Media Integrated with Transparent Oxide TFT Backplane

A novel architecture and proprietary electrically addressable inks have been developed to provide disruptive, print-like full color reflective digital media solutions based on an electrokinetic technology platform. The thin, flexible, low-power, reflective electronic media is fabricated with a new roll-to-roll manufacturing platform. Here we demonstrate the integration of this media with multi-component oxide (MCO) thin-film transistor (TFT) backplane for an active matrix reflective electronic display.

Multilevel Hierarchy of Fluorinated Wax on CuO Nanowires for Superoleophobic Surfaces

We demonstrate the multilevel hierarchy of nanoscale wax crystals on nanowire (NW) structures that strongly repels not only water but also olive oil and hexadecane. We deposited C24F50-fluorinated wax (F-wax) using thermal evaporation on the surface of CuO NWs. Fluorinated wax crystals are self-assembled on the CuO NWs forming three-dimensional hierarchical structures. The achieved multilevel hierarchy has strongly repelled water, glycerol, ethylene glycol, and olive oil with contact angles (CAs) exceeding 160°. When sufficient F-wax is crystallized on the CuO NWs, crystals that are assembled perpendicularly to the longitudinal NW axis form a re-entrant curvature allowing superoleophobic characteristics with strong repellence of hexadecane with CAs of ∼150° and a small contact angle hysteresis of <10°. Furthermore, the surfaces can repel extremely small water droplets (∼100 pL), an indication of an ability to withstand condensation. These types of multilevel hierarchies can be formed on numerous roughened surfaces as the wax can be easily applied to various substrates without affecting the mechanical integrity of base structures.

A High-Speed Optical Multidrop Bus for Computer Interconnections

Signal integrity constraints of high-speed electronics have made multidrop electrical buses infeasible. This high-speed alternative uses hollow metal waveguides and pellicle beam splitters that interconnect modules attached to the bus. With 1 mw of laser power, the bus can interconnect eight modules at 10 gbps per channel and achieves an aggregate bandwidth of more than 25 gbytes per second with 10-bit-wide signaling paths.

Three-Dimensional Triple Hierarchy Formed by Self-Assembly of Wax Crystals on CuO Nanowires for Nonwettable Surfaces

Novel hierarchical surfaces combining paraffin wax crystals and CuO nanowires are presented. We demonstrate a bioinspired hierarchical wax on nanowire (NW) structures having high water and ethylene glycol repellence. In general, vertically grown nanowire arrays can provide a superhydrophobic surface (SHS) due to extremely high surface roughness but cannot repel ethylene glycol. In this paper, C36H74 and C50H102 waxes are thermally evaporated on the surface of CuO NWs, forming highly ordered, three-dimensional (3D) hierarchical structures via self-assembly of wax crystals. These two and three level hierarchical structures provide perfect self-cleaning characteristics, with water contact angles (CAs) exceeding 170°. Furthermore, C36H74 and C50H102 wax crystals assembled perpendicularly to the longitudinal NW axis form a re-entrant (that is, a multivalued surface topography) curvature enabling high repellence to ethylene glycol (EG) with CAs exceeding 160°. We analyze the wettability dependence on wax crystal size and structure for the optimization of nonwettable hierarchical structured surfaces.

Novel flexible reflective color media with electronic inks

A novel architecture and proprietary electronic inks were developed to provide disruptive digital-media solutions based on an electrokinetic technology platform. The flexible reflective electronic media (eMedia) was fabricated by imprinting three-dimensional microscale structures with a roll-to-roll manufacturing platform. The HP technologies enable the required attributes for eMedia, such as low power, transparency, print-quality color, continuous levels of gray, and low-cost scalability. Pixelation was also demonstrated by integrating with the prototype oxide thin-film transistor backplane, and the system architecture was further developed by stacking primary-colorant layers for color reflective-display application. The innovations described in this paper are currently being developed further for the eSkins, eSignage, and ePaper applications.

Enhanced Detection of Broadband Incoherent Light with Nanoridge Plasmonics

Emerging photonic integrated circuit technologies require integrative functionality at ultrahigh speed and dimensional compatibility with ultrasmall electronics. Plasmonics offers a promise of addressing these challenges with novel nanophotonic approaches for on-chip information processing or sensing applications. Short communication range and strong light-matter interaction enabled by on-chip plasmonics allow us to extend beyond a conventional approach of integrating coherent and narrowband light source. Such hybrid electronic and photonic interconnection desires a on-chip photodetector that is highly responsive to broadband incoherent light, yet provides elegant design for nanoscale integration. Here we demonstrate an ultracompact broadband photodetection with greatly enhanced photoresponsivity using plasmonic nanoridge geometry. The nanoridge photodetector confines a wide spectrum of electromagnetic energy in a nanostructure through the excitation of multiple plasmons, which thus enables the detection of weak and broadband light. With nanoscale design, material, and dimensional compatibility for the integration, the nanoridge photodetector opens up a new possibility of highly sensitive on-chip photodetection for future integrated circuits and sensing applications.

Optimal Determination of the Fabrication Parameters in Focused Ion Beam for Milling Gold Nano Hole Array

Though focused ion beam (FIB) is one of the candidates to fabricate the nanoscale patterns, precision milling of nanoscale structures is not straightforward. Thus this poses challenges for novice FIB users. Optimal determination in FIB parameters is a crucial step to fabricate a desired nanoscale pattern. There are two main FIB parameters to consider, beam current (beam size) and dose (beam duration) for optimizing the milling condition. After fixing the dose, the proper beam current can be chosen considering both total milling time and resolution of the pattern. Then, using the chosen beam current, the metal nano hole structure can be perforated to the required depth by varying the dose. In this experiment, we found the adequate condition of 0.1 nC/μm² dose at 1 pA Ga ion beam current for 100 nm thickness perforation. With this condition, we perforated the periodic square array of elliptical nano holes.

Contact Transfer Printing of Side Edge Prefunctionalized Nanoplasmonic Arrays for Flexible microRNA Biosensor

For a nanoplasmonic approach of wearable biochip platform, understanding correlation between near‐field enhancement on nanostructures and sensing capability is a crucial step to improve the sensitivity in biosensing. A novel and effective method is demonstrated to increase sensitivity with the enhanced electric fields and to reduce noise with targeted functionalization enabled by transferring side edge prefunctionalized (SEPF) nanostructure arrays onto flexible substrates. Nanostructure sidewalls have selective biochemically functional terminals for the hybridization of microRNAs (miRNAs) and the immobilization of resonant nanoparticles, thus forming hetero assemblies of the nanostructure and the nanoparticles. The unique configuration has shown ultrasensitive biosensing of miRNA‐21 in a 10 × 10−15 m level by a red‐shift in scattering spectra induced by a plasmon coupling. This ultrasensitive SEPF nanostructure arrays are fabricated on a flexible substrate using a contact transfer printing with a release layer of trichloro(1H, 1H, 2H, 2H‐perfluorooctyl)silane. The introduction of the release layer at a prefunctionalizing step has proven to provide selective functionalization only on the sidewalls of the nanostructures. This reduces a background noise caused by the scattering from nonspecifically bound nanoparticles on the substrate, thus enabling reliable and precise detection.