Reconstruction-dependent electron-hole recombination on GaAs(001) surfaces studied by using near-surface quantum wells

1996 ◽  
Vol 53 (12) ◽  
pp. 7880-7883 ◽  
Author(s):  
Hiroshi Yamaguchi ◽  
Kiyoshi Kanisawa ◽  
Yoshiji Horikoshi
Keyword(s):  
Quantum Wells ◽  
Electron Hole ◽  
Near Surface ◽  
Hole Recombination

Formation Mechanism and Recombination-Enhanced Dissociation of a Hydrogen-Carbon Complex in Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
Yoichi Kamiura ◽  
Fumio Hashimoto ◽  
Minoru Yoneta
Keyword(s):  
Formation Mechanism ◽  
Chemical Etching ◽  
Surface Region ◽  
Electronic Energy ◽  
Hydrogen Atoms ◽  
Electron Hole ◽  
Near Surface ◽  
Depth Profiles ◽  
Schottky Structure ◽  
Hole Recombination

ABSTRACTWc have found that chemical etching induced an electron trap E3 (0.15) into n-typc Si. We attribute this trap to a hydrogen-carbon complex on the basis of available experimental data. By measuring DLTS depth profiles of the E3 trap, we propose a model of the formation mechanism of the hydrogen-carbon complex as follows. Hydrogen atoms arc adsorbed on the Si surface to terminate Si dangling bonds during chemical etching, and after the etching some unstably adsorbed ones diffuse into the near-surface region of silicon and are trapped by carbon to form the complex. The E3 trap is stable up to 100δC in the dark but is annihilated by the illumination of band gap light around 250K only outside the depletion layer of the Schottky structure. This provides unambiguous experimental evidence for the recombination-enhanced dissociation, in which the electronic energy released by the electron-hole recombination at the E3 level is converted into local kinetic energy of hydrogen to be released from carbon.

Origins of Parasitic Emissions from 353 nm AlGaN-based UV LEDs over SiC Substrates

2005 ◽  
Vol 892 ◽  
Author(s):  
Ji-Soo Park ◽  
Daryl W Fothergill ◽  
Patrick Wellenius ◽  
Seann M. Bishop ◽  
John F. Muth ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Optically Pumped ◽  
Electron Hole ◽  
Capping Layer ◽  
Uv Emission ◽  
Broad Emission ◽  
Shoulder Peak ◽  
P Type ◽  
Uv Leds ◽  
Hole Recombination

AbstractThe effects of p-GaN capping layers and p-type carrier-blocking layers on the occurrence of parasitic emissions from 353 nm AlGaN-based LEDs have been investigated. LEDs without a p-type Al0.25Ga0.75N carrier-blocking layer showed a shoulder peak at ∼370 nm due to electron overflow into the p-Al0.10Ga0.90N cladding layer and subsequent electron-hole recombination in the acceptor levels. Broad emission between 380 and 450 nm from LEDs having a p-GaN capping layer was caused by 420 nm luminescence from the p-GaN capping layer, which was optically pumped by 353 nm UV emission from the quantum wells. Broad, defect-related luminescence at ∼520 nm was emitted from the AlGaN layers within the quantum wells.

Article

1998 ◽  
Vol 76 (2) ◽  
pp. 105-110
Author(s):  
S S De ◽  
A K Ghosh ◽  
M Bera
Keyword(s):  
Quantum Wells ◽  
Decay Time ◽  
Carrier Density ◽  
Laser Intensity ◽  
Optical Excitation ◽  
Photoluminescence Spectra ◽  
Electron Hole ◽  
73.20 Dx ◽  
Excitation Conditions ◽  
Hole Recombination

Some physical characteristics of photoluminescence spectra in GaAs--(Ga,Al)As quantum-wells under steady optical excitation conditions are presented. They are based on the dependence of photoluminescence on laser intensity. The variations of carrier density with laser intensity and electron--hole recombination decay time are compared with earlier experimental results. PACS Nos. 73.20 Dx, 73.20 Mf

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

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.

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

1999 ◽  
Vol 40 (4-5) ◽  
pp. 123-130 ◽  
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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