Search results for: J.H. Warner

Items from 1 to 19 out of 19 results

chapter

Impact of mechanical strain on the charge collection mechanisms of nanometer scaled SOI devices under heavy ion and pulsed laser irradiation

M. Gaillardin, M. Raine, O. Duhamel, S. Girard, more

2013 14th European Conference on Radiation and Its Effects on Components and Systems (RADECS) > 1 - 7

2013 14th European Conference on Radiation and Its Effects on Components and Systems (RADECS)

We investigate the impact of performance boosters using mechanical stress on the Single-Event Transient (SET) response of nanometer scaled Fully-Depleted Silicon-On-Insulator (SOI) devices. Heavy ion-induced charge collection mechanisms are analyzed through the measurement of fast transients on dedicated test structures processed either on standard relaxed or bi-axially tensile strained SOI substrates.

article

The Doctor in early Cold War America

J.H. Warner

The Lancet > 2013 > 381 > 9876 > 1452-1453

chapter

Bandgap engineering achieved with doping superlattices

M.K. Yakes, C.D. Cress, M.P. Lumb, J.H. Warner, more

2012 38th IEEE Photovoltaic Specialists Conference > 2979 - 2984

2012 IEEE 38th Photovoltaic Specialists Conference (PVSC)

Tailoring bandgaps by introducing quantum wells into the intrinsic region of a solar cell has been shown to improve the energy conversion of these devices. Doping superlattices are a potential way to achieve sub-bandgap absorption in a photovoltaic device without the need to introduce additional materials or strain balancing. In this paper we investigate the inclusion of doping superlattices in between...

article

PND9 Huntington's Disease (HD) Direct Medical Costs: A Retrospective Claims Database Analysis

V. Divino, P. Smith, M. DeKoven, J.H. Warner, more

Value in Health > 2012 > 15 > 4 > A142

article

In-situ deposition of sparse vertically aligned carbon nanofibres on catalytically activated stainless steel mesh for field emission applications

M.T. Cole, K. Hou, J.H. Warner, J.S. Barnard, more

We report on an inexpensive, facile and industry viable carbon nanofibre catalyst activation process achieved by exposing stainless steel mesh to an electrolyzed metal etchant. The surface evolution of the catalyst islands combines low-rate electroplating and substrate dissolution. The plasma enhanced chemical vapour deposited carbon nanofibres had aspect-ratios >150 and demonstrated excellent...

article

Radiation Damage in Type II Superlattice Infrared Detectors

E.M. Jackson, E.H. Aifer, C.L. Canedy, J.A. Nolde, more

Journal of Electronic Materials > 2010 > 39 > 7 > 852-856

The effects of 2 MeV proton irradiation on a set of four long-wave infrared type II superlattice photodiodes with various structures were studied. Changes were monitored in operating bias, quantum efficiency (QE), and dark current. Shifts in operating bias indicate that irradiation causes the superlattices to become more p-type, and decreases in QE are found to be consistent with a reduction in carrier...

article

Controlling dark current in type-II superlattice photodiodes

C.L. Canedy, E.H. Aifer, J.H. Warner, I. Vurgaftman, more

Infrared Physics and Technology > 2009 > 52 > 6 > 326-334

Limiting the defect-mediated dark currents in type-II superlattice (T2SL) IR photodiodes remains the key challenge to focal plane arrays (FPAs) based on this material system. In spite of its larger effective mass to suppress tunneling and more than an order of magnitude longer Auger lifetime, the T2SL photodiode performance still lags behind that of the incumbent HgCdTe-based technology. The tunneling...

chapter

Non-linear behaviors of dark current slope in P⁺N GaAs solar cells following proton irradiations

Xiao Jie Chen, H.J. Barnaby, J.H. Warner, S.R. Messenger, more

2009 34th IEEE Photovoltaic Specialists Conference (PVSC) > 1565 - 1570

2009 34th IEEE Photovoltaic Specialists Conference (PVSC 2009)

In this paper, the dark current responses of p⁺n GaAs solar cells are measured before and after 2 MeV proton irradiations. The responses indicate that the dark current slope is not only a function of applied forward bias, but changes with proton fluence. The change in the dark current slope behavior can be modeled by Shockley-Reed-Hall (SRH) recombination statistics as a buildup of bulk traps in the...

chapter

Low temperature quantum efficiency measurements on irradiated multijunction solar cells

S.R. Messenger, J.H. Warner, P.P. Jenkins, R.J. Walters, more

2008 33rd IEEE Photovolatic Specialists Conference > 1 - 4

2008 33rd IEEE Photovolatic Specialists Conference (PVSC)

This paper presents quantum efficiency (QE) measurements and analyses on monolithic triple junction (3J) InGaP/GaAs/Ge solar cells under both room (300K) and low temperature (130K) conditions. In measuring the quantum efficiency of multijunction solar cells, one must be careful to use the proper bias conditions to isolate the subcell of interest. This may be achieved by using external light sources...

article

Effect of Proton and Silicon Ion Irradiation on Defect Formation in GaAs

J.H. Warner, C. Inguimbert, M.E. Twigg, S.R. Messenger, more

IEEE Transactions on Nuclear Science > 2008 > 55 > 6-1 > 3016 - 3024

Electrical and structural changes in GaAs are monitored using electron beam induced current (EBIC) and transmission electron microscopy (TEM) measurements after irradiation by protons and silicon ions. It has been determined that higher energy protons (E ges 10 MeV) and silicon ions disordered regions that are electrically and structurally different than those produced by lower energy protons. The...

article

Displacement Damage Evolution in GaAs Following Electron, Proton and Silicon Ion Irradiation

J.H. Warner, S.R. Messenger, R.J. Walters, G.P. Summers, more

IEEE Transactions on Nuclear Science > 2007 > 54 > 6-1 > 1961 - 1968

We characterize radiation induced defects in n-type GaAs following electron, proton, and silicon ion irradiations using deep level transient spectroscopy (DLTS) and electron beam induced current (EBIC) measurements. EBIC micrographs show the existence of radiation induced recombination centers following high energy proton (E MeV) or 22 MeV silicon ion irradiations, which were not observed following...

article

Antimonide Type-II “W” Photodiodes with Long-Wave Infrared R ₀ A Comparable to HgCdTe

C.L. Canedy, E.H. Aifer, I. Vurgaftman, J.G. Tischler, more

Journal of Electronic Materials > 2007 > 36 > 8 > 852-856

The recent development of graded-gap W-structured superlattices (GG-Ws) has led to a substantial improvement in the dark current performance of infrared photodiodes implemented with type-II superlattices (T2SLs). A study of ten GG-W photodiode wafers with 50% power responsivity cutoffs from 9 μm to 13.4 μm is presented. Dark current performance has increased by a factor of 10 over that of previous...

article

Correlation of Electron Radiation Induced-Damage in GaAs Solar Cells

J.H. Warner, S.R. Messenger, R.J. Walters, G.P. Summers, more

IEEE Transactions on Nuclear Science > 2006 > 53 > 4-1 > 1988 - 1994

GaAs solar cells with different structures and polarities were irradiated with 1 and 5 MeV electrons. The energy dependence of the electron damage coefficients for the photocurrent, photovoltage, and maximum power were found to vary approximately linearly with NIEL in contrast to what has been found for other GaAs cells

chapter

Correlation of Electron Radiation Induced-Damage in GaAs Solar Cells

J.H. Warner, S.R. Messenger, R.J. Walters, G.P. Summers, more

2005 8th European Conference on Radiation and Its Effects on Components and Systems > PG5-1 - PG5-6

8th European Conference on Radiation and its Effects on Components and Systems

chapter

Modelling low energy proton radiation effects on solar cells

S.R. Messenger, E.A. Burke, T.L. Morton, G.P. Summers, more

3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of > 1 > 716 - 719 Vol.1

3rd World Conference on Photovoltaic Energy Conversion

Past work has shown that the degradation of gallium arsenide solar cells in space radiation environments can be described with a single curve for a wide range of incident particle energies using the displacement damage dose (D/sub d/) approach. This greatly simplifies the prediction of the performance of GaAs solar cells exposed to complex particle spectra. A similar approach has not been applied...

chapter

Radiation hard, double-graded, drift-dominated InP solar cells

Yanning Sun, J.M. Woodall, J.H. Warner, R.J. Walters, more

3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of > 1 > 726 - 729 Vol.1

3rd World Conference on Photovoltaic Energy Conversion

Double-graded and drift-dominated InP solar cells have been designed, fabricated and characterized. By grading the doping concentration in both the emitter and the base of the InP solar cell, we create an electric field through the active layer, and thus efficiently collect carriers by drift which results in higher than 80% overall internal quantum efficiency. By adding an InP P/sup ++/ delta doped...

chapter

High energy proton degradation in GaAs solar cells

J.H. Warner, R.J. Walters, S.R. Messenger, G.P. Summers

3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of > 1 > 712 - 715 Vol.1

3rd World Conference on Photovoltaic Energy Conversion

In this paper we compare the energy dependences (1-500 MeV) of the proton damage coefficients for p/sup +/n GaAs solar cells with previously reported calculations of nonionizing energy loss (NIEL). For proton energies E<10 MeV, the damage coefficients all follow an approximate 1/E dependence. For E>10 MeV, the damage coefficients vary but are bounded by the total and elastic NIEL.

chapter

Alternate functions to describe solar cell degradation

S.R. Messenger, E.A. Burke, G.P. Summers, R.J. Walters, more

3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of > 1 > 720 - 722 Vol.1

3rd World Conference on Photovoltaic Energy Conversion

We have found that the empirical function described in the JPL Solar Cell Radiation Handbooks can describe the degradation of solar cell parameters for many solar cell technologies. In particular, when the degradation is presented in terms of displacement damage dose (D/sub d/), they permit a quantitative description of the response for protons over a wide energy range. Here we show that several of...

article

The safety and efficacy of short course (5-day) moxifloxacin vs. azithromycin in the treatment of patients with acute exacerbation of chronic bronchitis

C.A. DEABATE, C.P. MATHEW, J.H. WARNER, A. HEYD, more

Respiratory Medicine > 2000 > 94 > 11 > 1029-1037

Chronic bronchitis is common among adults and infectious exacerbations contribute considerably to morbidity and mortality. We aimed to compare the safety and efficacy of moxifloxacin to azithromycin for the treatment of patients with acute exacerbations of chronic bronchitis (AECB) of suspected bacterial origin.Between October 1998 and April 1999, 567 patients with AECB were enrolled at 37 centers...

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