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

Carrier concentration profiles of two-dimensional electron gases are investigated in wurtzite, Ga-face AlxGa1−xN/GaN/AlxGa1−xN and N-face GaN/AlxGa1−xN/GaN heterostructures used for the fabrication of field effect transistors. Analysis of the measured electron distributions in heterostructures with AlGaN barrier layers of different Al concentrations (0.15<x<0.5) and thickness between 20 and 65 nm demonstrate the important role of spontaneous and piezoelectric polarization on the carrier confinement at GaN/AlGaN and AlGaN/GaN interfaces. Characterization of the electrical properties of nominally undoped transistor structures reveals the presence of high sheet carrier concentrations, increasing from 6×1012 to 2×1013 cm−2 in the GaN channel with increasing Al-concentration from x=0.15 to 0.31. The observed high sheet carrier concentrations and strong confinement at specific interfaces of the N- and Ga-face pseudomorphic grown heterostructures can be explained as a consequence of interface charges induced by ...

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Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures

Wide bandgap semiconductors are extremely attractive for the gamut of power electronics applications from power conditioning to microwave transmitters for communications and radar. Of the various materials and device technologies, the AlGaN/GaN high-electron mobility transistor seems the most promising. This paper attempts to present the status of the technology and the market with a view of highlighting both the progress and the remaining problems.

AlGaN/GaN HEMTs-an overview of device operation and applications

Materials research plays a vital role in transforming breakthrough scientific ideas into next-generation technology. Similar to the way silicon revolutionized the microelectronics industry, the proper materials can greatly impact the field of plasmonics and metamaterials. Currently, research in plasmonics and metamaterials lacks good material building blocks in order to realize useful devices. Such devices suffer from many drawbacks arising from the undesirable properties of their material building blocks, especially metals. There are many materials, other than conventional metallic components such as gold and silver, that exhibit metallic properties and provide advantages in device performance, design flexibility, fabrication, integration, and tunability. This review explores different material classes for plasmonic and metamaterial applications, such as conventional semiconductors, transparent conducting oxides, perovskite oxides, metal nitrides, silicides, germanides, and 2D materials such as graphene. This review provides a summary of the recent developments in the search for better plasmonic materials and an outlook of further research directions.

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Alternative Plasmonic Materials: Beyond Gold and Silver

The role of extended and point defects, and key impurities such as C, O, and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation, and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes, and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics.

Gan : processing, defects, and devices

We construct a prime symmetry relation for integers that is equivalent to Goldbach's conjecture and show that numerical computations of this prime symmetry property strongly resemble a chaotic sequence We define and examine the notions of global and local prime quasientropies Finally, we employ the fact that the prime number sequence satisfies the property of deterministic randomness to consider its utility for the field of quantum computation

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Prime Quasientropy and Quasichaos

In this paper we report on our recent progress in using photonic digital-analog converters for arbitrary waveform generation. Optical arbitrary waveforms are generated using a time-domain approach based on an interfere metric modulator device.

High Speed Arbitrary Waveform Generation and Processing using a Photonic Digital-to-Analog Converter

Ultra fast photonics produce a wide spectrum coverage which is useful in producing fast waveforms of wide bandwidth with prescribed arbitrary amplitude and shapes. We will survey several arbitrary waveform generation techniques.

Integrated photonic digital-to-analog converter for arbitrary waveform generation

We demonstrate high-reflectivity crack-free Al 0.18 Ga 0.82 N/Al 0.8 Ga 0.2 N distributed Bragg reflectors (DBR) and monolithic microcavities grown by molecular beam epitaxy on thick c-axis GaN templates. The elastic strain energy in the epilayer is minimized by compensating the compressive and tensile stress in every period of the DBR structure. A 25 period DBR mirror provides a 26nm-wide stop band centered at 347 nm with the maximum reflectivity higher than 99%. The high-reflectivity DBRs can be used to form high Q -factor monolithic AlGaN/AlGaN microcavities. INTRODUCTION High-reflectivity distributed Bragg reflect ors (DBR) in the ultraviolet region ar e essential for the development of GaN-based optical devices. In particular, the region around 350 nm is important for devices containing pure GaN as an active medium. The growth of DBRs remains challenging in the nitrid e system. The difficulty lies in maintaining the structural integrity of a relatively thick structure that contains materials with a large lattice constant mismatch and different thermal expansion coefficients. Only a few groups have reported high-reflectivity Al

http://manfragroup.org/wp-content/uploads/2014/12/High-quality-UV-AlGaN-AlGaN-distributed-Bragg-reflectors-and-microcavities.pdf

High quality UV AlGaN/AlGaN distributed Bragg reflectors and microcavities

Local oscillator signal generation with low phase-noise is an important topic for future communications systems operating in D-band and beyond. This paper presents a D-band fundamental reflection-type source with high DC-to-RF efficiency and low phase-noise properties, realized using a transferred-substrate (TS) $\mathbf{0.8} \mu \mathbf{m}$ InP-DHBT process. It delivers 9.5 dBm peak output power, with 2 GHz tuning range. The DC consumption is only 43.5 mW from a single 2.5 volts power supply, which corresponds to 20 % peak DC-to-RF efficiency. The measured single side band (SSB) phase noise reaches −94 dBc/Hz and −115 dBc/Hz at 1 MHz and 10 MHz offset frequency, respectively. To the knowledge of the authors, this is the highest DC-to-RF efficiency reported so far in this frequency range with excellent phase noise performance and state-of-the-art output power.

Nils Weimann

Papers

Prime Quasientropy and Quasichaos

High Speed Arbitrary Waveform Generation and Processing using a Photonic Digital-to-Analog Converter

Integrated photonic digital-to-analog converter for arbitrary waveform generation

High quality UV AlGaN/AlGaN distributed Bragg reflectors and microcavities

Highly Efficient D-Band Fundamental Frequency Source Based on InP-DHBT Technology