Investigation of Electron–Hole Recombination-Activated Partial Dislocations and Their Behavior in 4H-SiC Epitaxial Layers

Electron-hole recombination activated Shockley partial dislocations bounding expanding stacking faults and their interactions with threading dislocations have been studied in 4H-SiC epitaxial layers using synchrotron x-ray topography. The bounding partials appear as white stripes or narrow dark lines in back-reflection X-ray topographs recorded using the basal plane reflections. Such contrast variations are attributable to the defocusing/focusing of the diffracted X-rays due to the edge component of the partial dislocations, which creates a convex/concave distortion of the basal planes. Simulation results based on the ray-tracing principle confirm our argument. The sign of the partial dislocations can be subsequently determined.

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Effect of Bipolar Gate-to-Drain Current on the Electrical Properties of Vertical Junction Field Effect Transistors

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.719 ◽

2009 ◽

Vol 615-617 ◽

pp. 719-722 ◽

Cited By ~ 7

Author(s):

Victor Veliadis ◽

Harold Hearne ◽

Eric J. Stewart ◽

Joshua D. Caldwell ◽

Megan Snook ◽

...

Keyword(s):

Field Effect ◽

Field Effect Transistors ◽

Stacking Faults ◽

Vertical Channel ◽

Drain Current ◽

Epitaxial Layers ◽

Electron Hole ◽

Blocking Voltage ◽

Hole Recombination ◽

Post Stress

Electron-hole recombination-induced stacking faults have been shown to degrade the I-V characteristics of SiC power p-n diodes and DMOSFETs with thick drift epitaxial layers. In this paper, we investigate the effect of bipolar gate-to-drain current on vertical-channel JFETs. The devices have n- drift epitaxial layers of 12-μm and 100-μm thicknesses, and were stressed at a fixed gate-to-drain current density of 100 A/cm2 for 500 hrs and 5 hrs, respectively. Significant gate-to-drain and on-state conduction current degradations were observed after stressing the 100-μm drift VJFET. Annealing at 350°C reverses the stress induced degradations. After 500 hours of stressing, the gate-to-source, gate-to-drain, and blocking voltage characteristics of the 12-μm VJFET remain unaffected. However, the on-state drain current was 79% of its pre-stress value. Annealing at 350°C has no impact on the post-stress on-state drain current of the 12-μm VJFET. This leads us to attribute the degradation to a “burn-in” effect.

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Determination of the Core-structure of Shockley Partial Dislocations in 4H-SiC

MRS Proceedings ◽

10.1557/proc-1069-d03-03 ◽

2008 ◽

Vol 1069 ◽

Author(s):

Yi Chen ◽

Ning Zhang ◽

Xianrong Huang ◽

Joshua D Caldwell ◽

Kendrick X Liu ◽

...

Keyword(s):

Contrast Variation ◽

Electron Hole ◽

X Ray ◽

Shockley Partial ◽

Partial Dislocations ◽

Bipolar Devices ◽

Simulation Based ◽

Hole Recombination

ABSTRACTSynchrotron x-ray topographs taken using basal plane reflections indicate that the electron-hole recombination activated Shockley partial dislocations in 4H silicon carbide bipolar devices appear as either white stripes with dark contrast bands at both edges or dark lines. In situ electroluminescence observations indicated that the mobile partial dislocations correspond to the white stripes in synchrotron x-ray topographs, while immobile partial dislocations correspond to the dark lines. Computer simulation based on ray-tracing principle indicates that the contrast variation of the partial dislocations in x-ray topography is determined by the position of the extra atomic half planes associated with the partial dislocations lying along their Peierls valley directions. The chemical structure of the Shockley partial dislocations can be subsequently determined unambiguously and non-destructively.

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Optically Detected Magnetic Resonance and Double Beam Photoluminescence of CdS/HgS/CdS Nanoparticles

MRS Proceedings ◽

10.1557/proc-536-257 ◽

1998 ◽

Vol 536 ◽

Author(s):

H. Porteanu ◽

A. Glozman ◽

E. Lifshitz ◽

A. Eychmüller ◽

H. Weller

Keyword(s):

Optical Properties ◽

Magnetic Resonance ◽

Cds Nanoparticles ◽

Electron Hole ◽

Cladding Layer ◽

Double Beam ◽

Optically Detected Magnetic Resonance ◽

Optically Detected ◽

Cladding Layers ◽

Hole Recombination

AbstractCdS/HgS/CdS nanoparticles consist of a CdS core, epitaxially covered by one or two monolayers of HgS and additional cladding layers of CdS. The present paper describes our efforts to identify the influence of CdS/HgS/CdS interfaces on the localization of the photogenerated carriers deduced from the magneto-optical properties of the materials. These were investigated by the utilization of optically detected magnetic resonance (ODMR) and double-beam photoluminescence spectroscopy. A photoluminescence (PL) spectrum of the studied material, consists of a dominant exciton located at the HgS layer, and additional non-excitonic band, presumably corresponding to the recombination of trapped carriers at the interface. The latter band can be attenuated using an additional red excitation. The ODMR measurements show the existence of two kinds of electron-hole recombination. These electron-hole pairs maybe trapped either at a twin packing of a CdS/HgS interface, or at an edge dislocation of an epitaxial HgS or a CdS cladding layer.

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Pre-Industrial Experience in Solar Photocatalytic Mineralization of Real Wastewaters. Application to Pesticide Container Recycling

Water Science & Technology ◽

10.2166/wst.1999.0583 ◽

1999 ◽

Vol 40 (4-5) ◽

pp. 123-130 ◽

Cited By ~ 2

Author(s):

S. Malato ◽

J. Blanco ◽

C. Richter ◽

B. Milow ◽

M. I. Maldonado

Keyword(s):

Organic Contaminants ◽

Toxic Waste ◽

Experimental Plant ◽

Electron Hole ◽

Particulate Suspensions ◽

Photocatalytic System ◽

Commercial Pesticide ◽

Pesticide Container ◽

By Products ◽

Hole Recombination

Particulate suspensions of TiO2 irradiated with natural solar tight in a large experimental plant catalyse the oxidation of organic contaminants. The problem in using TiO2 as a photocatalyst is electron/hole recombination. One strategy for inhibiting e−/h+ recombination is to add other (irreversible) electron acceptors to the reaction. In many highly toxic waste waters where degradation of organic pollutants is the major concern, the addition of an inorganic anion to enhance the organic degradation rate may be justified. For better results, these additives should fulfil the following criteria: dissociate into harmless by-products and lead to the formation of ·OH or other oxidising agents. In this paper, we attempt to demonstrate the optimum conditions for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant. The experiments were performed in one of the pilot plants of the largest solar photocatalytic system in Europe, the Detoxification Plants of the Plataforma Solar de Almería (PSA), in Spain. After testing ten different commercial pesticides, results show that peroxydisulphate enhances the photocatalytic miniralization of all of them. This study is part of an extensive project focused on the design of a solar photocatalytic plant for decontamination of agricultural rinsates in Almería (Spain).

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