GaAs‐on‐Si: Improved growth conditions, properties of undoped GaAs, high mobility, and fabrication of high‐performance AlGaAs/GaAs selectively doped heterostructure transistors and ring oscillators

The European Space Agency’s (ESA) ExoMars rover has recently been subject to a Phase A study led by EADS Astrium, UK. This rover mission represents a highly ambitious venture in that the rover is of considerable size ~200+kg with high mobility carrying a highly complex scientific instrument suite (Pasteur) of up to 40 kg in mass devoted to exobiological investigation of the Martian surface and sub-surface. The chassis design has been a particular challenge given the inhospitable terrain on Mars and the need to traverse such terrain robustly in order to deliver the scientific instruments to science targets of exobiological interest, We present some of the results and design issues encountered during the Phase A study related to the chassis. In particular, we have focussed on the overall tractive performance of a number of candidate chassis designs and selected the RCL (Science & Technology Rover Company Ltd in Russian) concept C design as the baseline option in terms of high performance with minimal mechanical complexity overhead. This design is a six-wheeled double-rocker bogie design to provide springless suspension and maintain approximately equal weight distribution across each wheel.

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Ab initio perspective of ultra-scaled CMOS from 2D-material fundamentals to dynamically doped transistors

npj 2D Materials and Applications ◽

10.1038/s41699-020-00181-1 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Aryan Afzalian

Keyword(s):

Field Effect ◽

High Performance ◽

Field Effect Transistor ◽

High Mobility ◽

Complementary Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Grand Challenge ◽

Gate Length ◽

Delay Performance ◽

Effect Transistor

AbstractUsing accurate dissipative DFT-NEGF atomistic-simulation techniques within the Wannier-Function formalism, we give a fresh look at the possibility of sub-10-nm scaling for high-performance complementary metal oxide semiconductor (CMOS) applications. We show that a combination of good electrostatic control together with high mobility is paramount to meet the stringent roadmap targets. Such requirements typically play against each other at sub-10-nm gate length for MOS transistors made of conventional semiconductor materials like Si, Ge, or III–V and dimensional scaling is expected to end ~12 nm gate-length (pitch of 40 nm). We demonstrate that using alternative 2D channel materials, such as the less-explored HfS2 or ZrS2, high-drive current down to ~6 nm is, however, achievable. We also propose a dynamically doped field-effect transistor concept, that scales better than its MOSFET counterpart. Used in combination with a high-mobility material such as HfS2, it allows for keeping the stringent high-performance CMOS on current and competitive energy-delay performance, when scaling down to virtually 0 nm gate length using a single-gate architecture and an ultra-compact design (pitch of 22 nm). The dynamically doped field-effect transistor further addresses the grand-challenge of doping in ultra-scaled devices and 2D materials in particular.

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High-mobility induced high-performance self-powered ultraviolet photodetector based on single ZnO microwire/PEDOT:PSS heterojunction via slight Ga-doping

Journal of Material Science and Technology ◽

10.1016/j.jmst.2021.03.047 ◽

2021 ◽

Author(s):

Peng Wan ◽

Mingming Jiang ◽

Tong Xu ◽

Yang Liu ◽

Caixia Kan

Keyword(s):

High Performance ◽

High Mobility ◽

Ultraviolet Photodetector ◽

Self Powered ◽

Ga Doping

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Quaternisation-polymerized N-type polyelectrolytes: synthesis, characterisation and application in high-performance polymer solar cells

Materials Horizons ◽

10.1039/c6mh00434b ◽

2017 ◽

Vol 4 (1) ◽

pp. 88-97 ◽

Cited By ~ 59

Author(s):

Zhicheng Hu ◽

Rongguo Xu ◽

Sheng Dong ◽

Kai Lin ◽

Jinju Liu ◽

...

Keyword(s):

Solar Cells ◽

High Performance ◽

Polymer Solar Cells ◽

High Mobility ◽

High Performance Polymer

We design and synthesize a series of high-mobility n-type polyelectrolytes with different anions via quaternisation polymerisation, which can be utilized as thickness-insensitive electron-transporting materials for polymer solar cells.

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Growth and Characterization of AllnGaN/InGaN Heterostructures

MRS Proceedings ◽

10.1557/proc-423-341 ◽

1996 ◽

Vol 423 ◽

Author(s):

J. C. Roberts ◽

F. G. Mcintosh ◽

M. Aumer ◽

V. Joshkin ◽

K. S. Boutros ◽

...

Keyword(s):

High Performance ◽

Visible Spectrum ◽

Growth Conditions ◽

Light Emitting ◽

Mocvd Growth ◽

Near Ultraviolet ◽

Active Layers ◽

Double Heterostructures ◽

Lattice Matched

AbstractThe emission wavelength of the InxGa1−xN ternary system can span from the near ultraviolet through red regions of the visible spectrum. High quality double heterostructures with these InxGa1−xN active layers are essential in the development of efficient optoelectronic devices such as high performance light emitting diodes and laser diodes. We will report on the MOCVD growth and characterization of thick and thin InGaN films. Thick InxGa1−xN films with values of x up to 0.40 have been deposited and their photoluminescence (PL) spectra measured. AlGaN/InGaN/AlGaN double heterostructures (DHs) have been grown that exhibit PL emission in the violet, blue, green and yellow spectral regions, depending on the growth conditions of the thin InGaN active layer. Preliminary results of an AllnGaN/InGaN/AllnGaN DH, with the potential of realizing a near-lattice matched structure, will also be presented.

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Determination of Caffeine Content in Tea and Maté Tea by using Different Methods

Czech Journal of Food Sciences ◽

10.17221/612-cjfs ◽

2009 ◽

Vol 27 (Special Issue 1) ◽

pp. S213-S216 ◽

Cited By ~ 18

Author(s):

D. Komes ◽

D. Horžić ◽

A. Belščak ◽

K. Kovačević Ganič ◽

A. Baljak

Keyword(s):

Antioxidant Capacity ◽

High Performance ◽

Antioxidant Properties ◽

Growth Conditions ◽

Hplc Method ◽

Frap Assay ◽

Chromatography Method ◽

Antioxidant Power ◽

Pharmaceutical Industries ◽

Mate Tea

Caffeine-containing products have been consumed for hundreds of years for their pleasant flavor and stimulating effects. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in five types of tea (white, yellow, green, oolong, black) and two types of maté tea (green maté and roasted maté tea). The content of caffeine was determined by using four different methods: extraction with chloroform, micromethod, method with lead-acetate and high performance liquid chromatography method (HPLC-PDA). The antioxidant capacity of teas as well as of the extracted (“raw”) caffeine was determined by using two methods: reactions with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS assay) and Ferric reducing antioxidant power (FRAP assay). The content of caffeine has been associated with plant origin and growth conditions, as well as processing conditions. By applying all four methods, the highest content of caffeine was determined in white tea, whereas maté and roasted maté tea were characterised with the lowest content of caffeine. Spectrophotometric micro-method has proven to be the best alternative to the HPLC method. The highest antioxidant capacity was determined in yellow tea, while the lowest was determined in roasted maté tea. In comparison to the antioxidant capacity of teas, the antioxidant capacity of extracted (“raw”) caffeine is almost negligible, and does not contribute to the overall antioxidant properties of tea.

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Orthogonal Time Sequency Multiplexing Modulation

10.36227/techrxiv.13580201.v1 ◽

2021 ◽

Author(s):

Tharaj Thaj ◽

Emanuele Viterbo

Keyword(s):

Time Domain ◽

Orthogonal Frequency Division Multiplexing ◽

High Performance ◽

High Mobility ◽

Low Complexity ◽

Modulation Scheme ◽

Frequency Space ◽

Time Frequency ◽

Single Carrier ◽

The Time Domain

This paper proposes <i>orthogonal time sequency multiplexing</i> (OTSM), a novel single carrier modulation scheme based on the well known Walsh-Hadamard transform (WHT) combined with row-column interleaving, and zero padding (ZP) between blocks in the time-domain. The information symbols in OTSM are multiplexed in the delay and sequency domain using a cascade of time-division and Walsh-Hadamard (sequency) multiplexing. By using the WHT for transmission and reception, the modulation and demodulation steps do not require any complex multiplications. We then propose two low-complexity detectors: (i) a simpler non-iterative detector based on a single tap minimum mean square time-frequency domain equalizer and (ii) an iterative time-domain detector. We demonstrate, via numerical simulations, that the proposed modulation scheme offers high performance gains over orthogonal frequency division multiplexing (OFDM) and exhibits the same performance of orthogonal time frequency space (OTFS) modulation, but with lower complexity. In proposing OTSM, along with simple detection schemes, we offer the lowest complexity solution to achieving reliable communication in high mobility wireless channels, as compared to the available schemes published so far in the literature.

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