Bulk Breakdown in AlGaN/GaN HFETs

1998 ◽  
Vol 512 ◽  
Author(s):  
G. Gradinaru ◽  
N. C. Kao ◽  
R. Gaska ◽  
J. Yang ◽  
Q. Chen ◽  
...  
Keyword(s):  
Light Emission ◽  
Large Range ◽  
Simultaneous Increase ◽  
Gate Current ◽  
Emission Signal ◽  
Multiplication Process ◽  
Breakdown Mechanism ◽  
Carrier Multiplication ◽  
Source Current

ABSTRACTA significant source current generated by a carrier multiplication process is observed at large drain voltages in the subthreshold regime, along with simultaneous increase of the gate current and light emission signal. Provided no on-surface premature breakdown takes place, a bulk channel avalanche breakdown process is proposed as the dominant breakdown mechanism for a large range of gate-to-source dc voltages. This process in the GaN channel is responsible for the excess source and drain currents, light emission, and excess gate current beyond its normal value measured in a gate-to-drain diode configuration. The role of the gate bias in controlling the channel vs. the gate breakdown mechanisms is described.

A Novel Optical System for Investigation on the Characteristics of Light Emission from Long Plasma Column

2012 ◽  
Vol 220-223 ◽  
pp. 2047-2051
Author(s):  
Xue Chen Li ◽  
Peng Ying Jia
Keyword(s):  
Optical System ◽  
Plasma Column ◽  
Barrier Discharge ◽  
Light Emission ◽  
Time Lag ◽  
Half Cycle ◽  
Charge Coupled Device ◽  
Emission Signal ◽  
Breakdown Mechanism ◽  
Intensified Charge Coupled Device

Although intensified charge coupled device (ICCD) is conventionally used to investigate the breakdown mechanism in gas discharge. ICCD can not be used to study the long plasma column because it is hard to be imaged. For solving this problem, a novel optical system is proposed which consists of several elements. Each element is composed of one collimator and a photomultiplier tube. Using this system, spatial resolved emission signal can be obtained. Results show that the light emission signal from each area shows a pulse with a width of about 3μs. It is interesting that the time lag in each half cycle increases with the increase of distance away from the dielectric barrier discharge (DBD). This phenomenon implies that the plasma bullet always leaves DBD at the rising edge of the applied voltage. The time lag versus the distance from DBD is used to calculate the propagation velocity of the discharge.

A Gate Breakdown Mechanism in Mesfets and HEMTs

1991 ◽  
Vol 241 ◽  
Author(s):  
R. J. Trew ◽  
T. A. Winslow ◽  
U. K. Mishra
Keyword(s):  
Experimental Data ◽  
Thermal Effects ◽  
Light Emission ◽  
Avalanche Breakdown ◽  
Gate Electrode ◽  
Gate Current ◽  
Versus Bias ◽  
Breakdown Mechanism ◽  
Assisted Tunneling ◽  
First Time

ABSTRACTA model for gate breakdown in MESFETs and HEMTs is proposed. The model is based upon a combination of thermally assisted tunneling and avalanche breakdown. When thermal effects are considered it is demonstrated that the model predicts increasing drain-source breakdown as the gate electrode is biased towards pinch-off, in agreement with experimental data. The model also predicts, for the first time, the gate current versus bias behavior observed in experimental data. The model is consistent with the various reports of breakdown and light emission phenomena reported in the literature.

The critical role of the coordination sphere in the high-efficiency blue-light emission from aminopyrazine metal-organic polymers

2021 ◽  
Vol 186 ◽  
pp. 109025
Author(s):  
João Humberto Dias Campos ◽  
Meiry Edivirges Alvarenga ◽  
Maykon Alves Lemes ◽  
José Antônio do Nascimento Neto ◽  
Freddy Fernandes Guimarães ◽  
...  
Keyword(s):  
Blue Light ◽  
Coordination Sphere ◽  
High Efficiency ◽  
Light Emission ◽  
Critical Role ◽  
Organic Polymers ◽  
Blue Light Emission ◽  
Metal Organic

Social and Familial Factors in the Development of Early Childhood Asthma

PEDIATRICS ◽  
1985 ◽  
Vol 75 (5) ◽  
pp. 859-868 ◽  
Author(s):  
L. J. Horwood ◽  
D. M. Fergusson ◽  
F. T. Shannon
Keyword(s):  
Early Childhood ◽  
Birth Cohort ◽  
Childhood Asthma ◽  
Proportional Hazards ◽  
Large Range ◽  
Significant Risk ◽  
Social Background ◽  
Familial Factors ◽  
The Family

The role of social and familial factors in the development of childhood asthma by age 6 years was studied in a birth cohort of New Zealand children. Rates of asthma varied markedly with the child's sex; boys had twice the rate of asthma as girls. In addition, the factors associated with asthma varied with the child's sex. For boys, wheeze during infancy, early eczema, and parental asthma were all significant risk factors; for girls, the only risk factor was early eczema. Proportional hazards modeling of the data failed to show any significant associations between the development of asthma and a large range of other social and familial factors including breast-feeding, parental smoking habits, pets in the child's family, stress in the family, or family social background. It was concluded that asthma in early childhood appeared to be inherited to some extent, its age of expression was related to the child's sex, and it had a complex interaction with other forms of allergic disease. There was no evidence to suggest that the structure, practices, or dynamics of the child's family played a significant role in the development of asthma for children in this birth cohort.

scholarly journals THE ORGANIZATION AND INNERVATION OF THE LUMINESCENT ORGAN IN A FIREFLY, PHOTURIS PENNSYLVANICA (COLEOPTERA)

1963 ◽  
Vol 16 (2) ◽  
pp. 323-359 ◽  
Author(s):  
David S. Smith
Keyword(s):  
Electron Microscope ◽  
Synaptic Vesicles ◽  
Light Emission ◽  
Nerve Endings ◽  
Tracheal Epithelium ◽  
Nerve Terminals ◽  
Tracheal System ◽  
Physiological Evidence ◽  
Effector System

The organization of the luminescent organ of an adult firefly has been studied with the electron microscope, and particular attention has been given to the disposition of nerve terminals within the organ. The cytological structure of the cells of the tracheal system, the peripheral and terminal axons, the photocytes and the cells of the dorsal ("reflecting") layer is described. Previous observations on the peripheral course of nerve branches alongside the tracheal trunks at the level of the dorsal layer and photocyte epithelium have been confirmed, and specialised nerve endings containing axoplasmic components structurally identical with "synaptic vesicles" and "neurosecretory droplets" have been identified, not in association with the surface of the photocytes, but lying between the apposed surfaces of two components of the tracheal epithelium: the tracheal end-cell and the tracheolar cell. These cytological findings are discussed in terms of available biochemical and physiological evidence concerning the mechanism of light emission in the firefly, especially with respect to the possible role of chemical "transmitter" action in triggering a response in a luminescent effector system.

scholarly journals Peculiarities of time-dependent-dielectric breakdown characteristics of pure and doped Ta2O5 stacks

2013 ◽  
Vol 26 (3) ◽  
pp. 281-296
Author(s):  
E. Atanassova ◽  
A. Paskaleva
Keyword(s):  
Dielectric Breakdown ◽  
Interface Layer ◽  
Time Dependent ◽  
Relative Impact ◽  
Time Dependent Dielectric Breakdown ◽  
Breakdown Mechanism ◽  
Number Of Factors ◽  
High K ◽  
Induced Defects

The effect of both the process-induced defects and the dopant on the time-dependent-dielectric breakdown in Ta2O5 stacks is discussed. The breakdown degradation is analyzed in terms of specific properties of high-k stacks which make their dielectric breakdown mechanism completely different from that of classical SiO2. The relative impact of a number of factors constituting the reliability issues in Ta2O5-based capacitors (trapping in pre-existing traps, stress-induced new traps generation, the presence of interface layer at Si and the role of the dopant) is clarified.

scholarly journals Osmolytes: Proline metabolism in plants as sensors of abiotic stress

2017 ◽  
Vol 9 (4) ◽  
pp. 2079-2092 ◽  
Author(s):  
Ashu Singh ◽  
Manoj Kumar Sharma ◽  
R. S. Sengar
Keyword(s):  
Stress Tolerance ◽  
Large Range ◽  
Plant Stress ◽  
Proline Accumulation ◽  
Metal Chelator ◽  
Low Concentrations ◽  
Plant Stress Tolerance ◽  
Higher Doses ◽  
Research Pattern

Proline accumulation occurs in a large range of plant species in retaliation to the numerous abiotic stresses. An exclusive research pattern suggests there is a pragmatic relation between proline accumulation and plant stress tolerance. In this review, we will discuss the metabolism of proline accumulation and its role in stress tolerance in plants. Pertaining to the literature cited clearly indicates that not only does it acts as an osmolyte, it also plays important roles during stress as a metal chelator and an antioxidative defence molecule. Moreover, when applied exogenously at low concentrations, proline enhanced stress tolerance in plants. However, some reports point out adverse effects of proline when applied at higher doses. Role of proline gene in seed germination, flowering and other developmental programmes; thus creation of transgene overexpressing this gene would provide better and robust plants. In this context this review gives a detailed account of different proline gene over-expressed in all the trans-genic crops so far.

Nanoconfining solution-processed organic semiconductors for emerging optoelectronics

2021 ◽  
Author(s):  
Yuze Zhang ◽  
Alina Chen ◽  
Min-Woo Kim ◽  
Aida Alaei ◽  
Stephanie S. Lee
Keyword(s):  
Charge Transport ◽  
Organic Semiconductors ◽  
Organic Semiconductor ◽  
Light Emission ◽  
Solution Processed ◽  
Semiconductor Crystals

This tutorial review highlights the role of nanoconfinement in selecting for orientations and polymorphs of organic semiconductor crystals that are optimized for optoelectronic processes, including charge transport and light emission.

Yucatec Land and Labor before and after Spanish Incursions

2020 ◽  
pp. 210-223
Author(s):  
Adolfo Iván Batún Alpuche ◽  
Patricia A. McAnany ◽  
Maia Dedrick
Keyword(s):  
Private Property ◽  
Large Range ◽  
Post Colonial ◽  
High Productivity ◽  
Intensive Production ◽  
Cozumel Island ◽  
Western Concept ◽  
Before And After

Yucatec land and labor arrangements before and after Spanish incursions are examined for ruptures and continuities. The Western concept of private property is found to ring hollow in a landscape in which intersecting spheres of authority (including those of supernaturals) guide protocols of access and extraction. Furthermore, no simple dichotomy between pre- and post-colonial can explain the range of land arrangements and networks of labor that existed across Yucatán. Through the input of labor or as a consequence of geomorphology, a patchwork of high-productivity micro-environments can be found across Yucatán and on Cozumel Island. Cultivation and/or extraction at these resource-intensive production zones encompassed a large range of labor arrangements and interdependencies during Pre-Columbian times. In general, land and labor are conceptualized as suspended within relationships of shifting authority. In reference to both land labor, authors break with the construct of “control over” and embrace the phrase “authority to,” which recognizes the role of negotiation and the inclusion of supernatural forces perceived to have played a structuring role in the disposition of land and labor.

Sign in / Sign up

Export Citation Format

Share Document