Zobrazeno 1 - 10
of 97
pro vyhledávání: '"R.H. Wallis"'
Publikováno v:
Small Ruminant Research. 121:280-288
a b s t r a c t Rhagodia preissii (Moq.) is a woody perennial shrub that is being investigated as a forage plant for livestock but some uncertainty about its potential exists because of its low accep- tance and variable intake by sheep. Initial evide
Autor:
Trevor Martin, W.A. Phillips, R.H. Wallis, Michael J. Uren, M. Walmsley, J.C. Birbeck, G C Crow, R A Davies, R. A. Abram, R.S. Balmer, S.K. Jones, B.T. Hughes, D.C. Herbert, D.G. Hayes
Publikováno v:
Journal of Physics: Condensed Matter. 14:3479-3497
Self-consistent Monte Carlo simulations are reported for AlGaN/GaN HFETs. Hot-carrier scattering rates are determined by fitting experimental ionization coefficients and the doping character of the GaN is obtained from substrate bias measurements. Pr
Autor:
D. Lee, S.K. Jones, R.S. Balmer, J.C. Birbeck, Michael J. Uren, R.H. Wallis, Trevor Martin, P. J. M. Parmiter, B.T. Hughes
Publikováno v:
Journal of Crystal Growth. 230:579-583
Undoped 28 nm AlGaN on 1 μm GaN was grown by MOVPE for high power microwave HFETs. Non-destructive methods for rapid characterisation of the layers are described. Double contact mercury probe capacitance voltage measurements gave valuable informatio
Publikováno v:
Journal of Crystal Growth. 230:569-572
This paper describes a comparison of material and device results obtained from AlGaN/GaN epitaxial HFET wafers from three commercial sources. Although all three sources supplied material to the same nominal specification, X-ray diffraction, Hall effe
Publikováno v:
Journal of Crystal Growth. 108:203-218
Compound and orientation dependent epitaxy (CODE) is a novel MOVPE phenomenon, applicable to the single step growth of low-dimensional devices and reduced dimensional structures such as quantum wires and quantum dots. This phenomenon arises in the gr
Autor:
P.J. Parmiter, T. Martin, D. Lee, B.T. Hughes, R.H. Wallis, M.J. Uren, J.C. Birbeck, A.J. Hydes
Publikováno v:
1999 Symposium on High Performance Electron Devices for Microwave and Optoelectronic Applications. EDMO (Cat. No.99TH8401).
MOVPE has been used to grow 2D electron gas layers with concentration 8/spl times/10/sup 12/ cm/sup -2/ and mobility 10/sup 30/ cm/sup 2//Vsec in a AlGaN/GaN heterostructure. Mesa isolated HFET devices have been fabricated using this material which s
Publikováno v:
1998 URSI International Symposium on Signals, Systems, and Electronics. Conference Proceedings (Cat. No.98EX167).
The features of GaInP/GaAs HBT technology are illustrated by a description of the advanced general purpose GMMT B20 process, which has f/sub T/ and f/sub max/ typically 50 GHz and a breakdown voltage BV/sub CEO/ in excess of 10 volts. This process ha
Publikováno v:
IEEE MTT/ED/AP/LEO Societies Joint Chapter United Kingdom and Republic of Ireland Section. 1997 Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications. EDMO (Cat. No.97TH8305).
An enhanced GaAs/InGaP HBT process has been developed at GMMT for the implementation of high performance digital and microwave circuit functions. Improvements have been made in device characteristics, with small area devices exhibiting current gain (
Publikováno v:
Electronics Letters. 31:921-922
A wideband optical receiver has been designed and fabricated. The gain with respect to 50 Omega is 12 dB from 2 to 20 GHz, and the noise spectral density is a maximum of 10 pA/ square root Hz between 6 and 18 GHz. The noise, gain and flatness perform
Publikováno v:
Electronics Letters. 30:422-423
A wideband low-noise pseudomorphic HEMT MMIC variable-gain amplifier has been designed and fabricated. The amplifier has a nominal gain of 13 dB across the band 2 – 20 GHz, with gain flatness better than ±0.4 dB. The noise figure is less than 3 dB