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

This paper addresses noise modeling of transfersubstrate indium phosphide double heterobipolar transistors (InP DHBTs). Transistors with an emitter area of 0.8 × 6 μm2 (single-finger) and 2 × 0.8 × 6 μm2 (double-finger) are measured and simulated. It turns out that the correlation of shot-noise sources is negligible for these devices, although it was found in earlier works to be essential to describe GaAs HBT noise behavior. As a result, the work provides the basis for reliable extrapolation of noise performance beyond the frequency range provided by standard noise measurement equipment.

Noise modeling of transferred-substrate InP-DHBTs

Toward Nanowire HBT: Reverse Current Reduction in Coaxial GaAs/InGaP n(i)p and n(i)pn Core-Multishell Nanowires

Metal organic vapor-phase epitaxy of GaN shells on N- and Ga-polar nanowires on AlN/Si(111) templates has been studied in detail. A polarity-dependent epitaxial optimization of nitride-based core–shell structures is necessary to attain the desired shell shape. On N-polar wires, a maximal shell length has been achieved using N2, only, as a carrier gas, while the length decreases by substitution of N2 with H2. A strong impact of the NW growth template polarity has been observed, which has to be considered to attain the desired shell shape. On Ga-polar wires under pure N2, an exclusive coverage of the wire tip occurs. Shell growth and an increasing shell length are obtained by injecting increased H2 flows. The semi-polar {101} and polar (000) planes have been identified as the facets that limit the vertical shell length growth evolution on the N- and Ga-polar core–shell structures, respectively. Meanwhile, the m-planar lateral growth mode is found to be identical for both types of polarities. The data are used to set up a growth model that includes the facet-dependent termination, carrier-gas dependent H-passivation, Ga-adatom length and Ga-adlayer formation, and the thereby adjusted three-dimensional growth and shell shape for both polarities. The attained insights and the developed technology allow the epitaxy of homogeneous complex crystal architectures, mandatory for optimized nitride core–shell NW-based devices.

A systematic study of Ga- and N-polar GaN nanowire–shell growth by metal organic vapor phase epitaxy

Ultrafast optoelectronic devices are useful in prescribing fast microwave and millimeter-wave waveforms of wide bandwidth and precision. An integrated InP PIC will be illustrated to demonstrate agile arbitrary waveform synthesis at time domain.

Photonic generation of microwave and millimeter-wave arbitrary waveforms

The traditional transmission coefficient present in the original Landauer formulation, which is valid for quasi-static scenarios with working frequencies below the inverse of the electron transit time, is substituted by a novel time-dependent displacement current coefficient valid for frequencies above this limit. Our model captures in a simple way the displacement current component of the total current, which at frequencies larger than the inverse of the electron transit time can be more relevant than the particle component. The proposed model is applied to compute the response of a resonant tunneling diode from 10 GHz up to 5 THz. We show that tunneling electron devices are intrinsically nonlinear at such high frequencies, even under small-signal conditions, due to memory effects related to the displacement current. We show that these intrinsic nonlinearities (anharmonicities) represent an advantage, rather than a drawback, as they open the path for tunneling devices in many THz applications, and avoid further device downscaling.

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Nils Weimann

Papers

Noise modeling of transferred-substrate InP-DHBTs

Toward Nanowire HBT: Reverse Current Reduction in Coaxial GaAs/InGaP n(i)p and n(i)pn Core-Multishell Nanowires

A systematic study of Ga- and N-polar GaN nanowire–shell growth by metal organic vapor phase epitaxy

Photonic generation of microwave and millimeter-wave arbitrary waveforms

There is Plenty of Room for THz Tunneling Electron Devices Beyond the Transit Time Limit