We present a comprehensive, up-to-date compilation of band parameters for the technologically important III–V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin-orbit, and crystal-field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split-off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy-composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.

Band parameters for III–V compound semiconductors and their alloys

An object of the present invention is to decrease the resistance of a power supply line, to suppress a voltage drop in the power supply line, and to prevent defective display. A connection terminal portion includes a plurality of connection terminals. The plurality of connection terminals is provided with a plurality of connection pads which is part of the connection terminal. The plurality of connection pads includes a first connection pad and a second connection pad having a line width different from that of the first connection pad. Pitches between the plurality of connection pads are equal to each other.

Semiconductor device and display device

A flexible single-crystalline PMN-PT piezoelectric energy harvester is demonstrated to achieve a self-powered artificial cardiac pacemaker. The energy-harvesting device generates a short-circuit current of 0.223 mA and an open-circuit voltage of 8.2 V, which are enough not only to meet the standard for charging commercial batteries but also for stimulating the heart without an external power source.

Self-Powered Cardiac Pacemaker Enabled by Flexible Single Crystalline PMN-PT Piezoelectric Energy Harvester

In this review article, we focus on the various types of materials used in biomedical implantable devices, including the polymeric materials used as substrates and for the packaging of such devices. Polymeric materials are used because of the ease of fabrication, flexibility, and their biocompatible nature as well as their wide range of mechanical, electrical, chemical, and thermal behaviors when combined with different materials as composites. Biocompatible and biostable polymers are extensively used to package implanted devices, with the main criteria that include gas permeability and water permeability of the packaging polymer to protect the electronic circuit of the device from moisture and ions inside the human body. Polymeric materials must also have considerable tensile strength and should be able to contain the device over the envisioned lifetime of the implant. For substrates, structural properties and, at times, electrical properties would be of greater concern. Section 1 gives an introduction o...

Polymeric Biomaterials for Medical Implants and Devices

The rapid development of information technology has led to urgent requirements for high efficiency and ultralow power consumption. In the past few decades, neuromorphic computing has drawn extensive attention due to its promising capability in processing massive data with extremely low power consumption. Here, we offer a comprehensive review on emerging artificial neuromorphic devices and their applications. In light of the inner physical processes, we classify the devices into nine major categories and discuss their respective strengths and weaknesses. We will show that anion/cation migration-based memristive devices, phase change, and spintronic synapses have been quite mature and possess excellent stability as a memory device, yet they still suffer from challenges in weight updating linearity and symmetry. Meanwhile, the recently developed electrolyte-gated synaptic transistors have demonstrated outstanding energy efficiency, linearity, and symmetry, but their stability and scalability still need to be optimized. Other emerging synaptic structures, such as ferroelectric, metal–insulator transition based, photonic, and purely electronic devices also have limitations in some aspects, therefore leading to the need for further developing high-performance synaptic devices. Additional efforts are also demanded to enhance the functionality of artificial neurons while maintaining a relatively low cost in area and power, and it will be of significance to explore the intrinsic neuronal stochasticity in computing and optimize their driving capability, etc. Finally, by looking into the correlations between the operation mechanisms, material systems, device structures, and performance, we provide clues to future material selections, device designs, and integrations for artificial synapses and neurons.

A comprehensive review on emerging artificial neuromorphic devices

We present a numerical model in which the thermionic and tunneling mechanisms across an abrupt heterojunction interface are taken into account on the basis of the one dimensional drift-diffusion formulation. We use an expression of thermionic-field emission current formulated based on the WKB approximation as a boundary condition at the abrupt heterointerface which eventually limits the current transport over the barrier while maintaining the current continuity. The I-V characteristics of three types of GaAs/AlGaAs heterojunctions are analyzed by varying device dimension, doping density, and temperature and compared with those obtained by the thermionic emission model to illustrate the significance of both tunneling and thermionic emission mechanisms. We demonstrate that the role of tunneling in the overall current transport is very important in these abrupt heterojunctions especially at high doping densities and low temperatures. In the case of an MBE-grown AlGaAs triangular heterojunction barrier, the temperature-dependent I-V characteristics are measured and compared with the theoretical results. Good agreement is obtained when the tunneling process is taken into account by employing the thermionic-field emission boundary condition presented here.

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Numerical modeling of abrupt heterojunctions using a thermionic-field emission boundary condition

Biointegrated electronics have been investigated for various healthcare applications which can introduce biomedical systems into the human body. Silicon-based semiconductors perform significant roles of nerve stimulation, signal analysis, and wireless communication in implantable electronics. However, the current large-scale integration (LSI) chips have limitations in in vivo devices due to their rigid and bulky properties. This paper describes in vivo ultrathin silicon-based liquid crystal polymer (LCP) monolithically encapsulated flexible radio frequency integrated circuits (RFICs) for medical wireless communication. The mechanical stability of the LCP encapsulation is supported by finite element analysis simulation. In vivo electrical reliability and bioaffinity of the LCP monoencapsulated RFIC devices are confirmed in rats. In vitro accelerated soak tests are performed with Arrhenius method to estimate the lifetime of LCP monoencapsulated RFICs in a live body. The work could provide an approach to flexible LSI in biointegrated electronics such as an artificial retina and wireless body sensor networks.

In Vivo Silicon-Based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers

Memristor devices based on electrochemical metallization operate through electrochemical formation/dissolution of nanoscale metallic filaments, and they are considered a promising future nonvolatile memory because of their outstanding characteristics over conventional charge-based memories. However, nanoscale conductive paths or filaments precipitated from the redox process of metallic elements are randomly formed inside oxides, resulting in unexpected and stochastic memristive switching parameters including the operating voltage and the resistance state. Here, we present the guided formation of conductive filaments in Ag nanocone/SiO2 nanomesh/Pt memristors fabricated by high-resolution nanotransfer printing. Consequently, the uniformity of the memristive switching behavior is significantly improved by the existence of electric-field concentrator arrays consisting of Ag nanocones embedded in SiO2 nanomesh structures. This selective and controlled filament growth was experimentally supported by analyzing ...

Reliable Memristive-Switching Memory Devices Enabled by Densely-Packed Silver Nanocone Arrays as Electric-Field Concentrators.

A microwave electric-field mapping system based on electrooptic sampling has been developed using micromachined GaAs crystals mounted on gradient index lenses and single-mode optical fibers. The probes are able to detect three orthogonal polarizations of electric fields and, due to the flexibility and size of the optical fiber, can be positioned not only from the extreme near-field to the far-field regions of microwave and millimeter-wave structures, but also inside of enclosures such as waveguides and packages.

Electric field mapping system using an optical-fiber-based electrooptic probe

High-speed, long-wavelength InAlAs/InGaAs OEIC photoreceivers based on a p-i-n/HBT shared layer integration scheme have been designed, fabricated and characterized. The p-i-n photodiodes, formed with the 6000 /spl Aring/-thick InGaAs precollector layer of the HBT as the absorbing layer, exhibited a responsivity of /spl sim/0.4 A/W and a -3 dB optical bandwidth larger than 20 GHz at /spl lambda/=1.55 /spl mu/m. The fabricated three-stage transimpedance amplifier with a feedback resistor of 550 /spl Omega/ demonstrated a transimpedance gain of 46 dB/spl Omega/ and a -3 dB bandwidth of 20 GHz. The monolithically integrated photoreceiver with a 83 /spl mu/m p-i-n photodiode consumed a small dc power of 35 mW and demonstrated a measured -3 dB optical bandwidth of 19.5 GHz, which is the highest reported to date for an InAlAs/InGaAs integrated front-end photoreceiver. The OEIC photoreceiver also has a measured input optical dynamic range of 20 dB. The performance of individual devices and integrated circuits was also investigated through detailed CAD-based analysis and characterization. Transient simulations, based on a HSPICE circuit model and previous measurements of eye diagrams for a NRZ 2/sup 31/-1 pseudorandom binary sequence (PRBS), show that the OEIC photoreceiver is capable of operation up to 24 Gb/s.

Kyounghoon Yang

Papers

Numerical modeling of abrupt heterojunctions using a thermionic-field emission boundary condition

In Vivo Silicon-Based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers

Reliable Memristive-Switching Memory Devices Enabled by Densely-Packed Silver Nanocone Arrays as Electric-Field Concentrators.

Electric field mapping system using an optical-fiber-based electrooptic probe

Design, modeling, and characterization of monolithically integrated InP-based (1.55 /spl mu/m) high-speed (24 Gb/s) p-i-n/HBT front-end photoreceivers