EXCITONS, LOCALIZED STATES IN SILICON DIOXIDE AND RELATED CRYSTALS AND GLASSES

2000 ◽  
pp. 235-283 ◽  
Author(s):  
A. N. Trukhin
Keyword(s):  
Silicon Dioxide ◽  
Localized States

Luminescence of silicon Dioxide — silica glass, α-quartz and stishovite

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Anatoly Trukhin ◽  
Krishjanis Smits ◽  
Georg Chikvaidze ◽  
Tatiana Dyuzheva ◽  
Ludmila Lityagina
Keyword(s):  
Silicon Dioxide ◽  
Silica Glass ◽  
Quartz Crystal ◽  
Single Photon ◽  
Localized States ◽  
Two Photon ◽  
Pure Silica ◽  
Photon Excitation ◽  
Radiation Induced ◽  
Arf Laser

AbstractThis paper compares the luminescence of different modifications of silicon dioxide — silica glass, α-quartz crystal and dense octahedron structured stishovite crystal. Under x-ray irradiation of pure silica glass and pure α-quartz crystal, only the luminescence of self-trapped exciton (STE) is detected, excitable only in the range of intrinsic absorption. No STE luminescence was detected in stishovite since, even though its luminescence is excitable below the optical gap, it could not be ascribed to a self-trapped exciton. Under ArF laser excitation of pure α-quartz crystal, luminescence of a self-trapped exciton was detected under two-photon excitation. In silica glass and stishovite mono crystal, we spectrally detected mutually similar luminescences under single-photon excitation of ArF laser. In silica glass, the luminescence of an oxygen deficient center is presented by the so-called twofold coordinated silicon center (L.N. Skuja et al., Solid State Commun. 50, 1069 (1984)). This center is modified with an unknown surrounding or localized states of silica glass (A.N. Trukhin et al., J. Non-Cryst. Solids 248, 40 (1999)). In stishovite, that same luminescence was ascribed to some defect existing after crystal growth. For α-quartz crystal, similar to silica and stishovite, luminescence could be obtained only by irradiation with a lattice damaging source such as a dense electron beam at a temperature below 80 K, as well as by neutron or -irradiation at 290 K.In spite of a similarity in the luminescence of these three materials (silica glass, stishovite mono crystal and irradiated α-quartz crystal), there are differences that can be explained by the specific characteristics of these materials. In particular, the nature of luminescence excited in the transparency range of stishovite is ascribed to a defect existing in the crystal after-growth. A similarity between stishovite luminescence and that of oxygen-deficient silica glass and radiation induced luminescence of α-quartz crystal presumes a similar nature of the centers in those materials.

LOCALIZED STATES AND BAND STRUCTURE

1972 ◽  
Vol 33 (C3) ◽  
pp. C3-21-C3-25 ◽  
Author(s):  
F. BASSANI
Keyword(s):  
Band Structure ◽  
Localized States

COMPARISON OF OPTICALLY INDUCED LOCALIZED STATES IN CHALCOGENIDE GLASSES AND THEIR CRYSTALLINE COUNTERPARTS

1981 ◽  
Vol 42 (C4) ◽  
pp. C4-383-C4-386 ◽  
Author(s):  
S. G. Bishop ◽  
B. V. Shanabrook ◽  
U. Strom ◽  
P. C. Taylor
Keyword(s):  
Chalcogenide Glasses ◽  
Localized States ◽  
Optically Induced

Buckling Control of Silicon Dioxide Diaphragms for Sensitivity Enhancement of Piezoelectric Ultrasonic Microsensors

2011 ◽  
Vol 131 (7) ◽  
pp. 235-239 ◽  
Author(s):  
Kaoru Yamashita ◽  
Tomoya Yoshizaki ◽  
Minoru Noda ◽  
Masanori Okuyama
Keyword(s):  
Silicon Dioxide ◽  
Sensitivity Enhancement

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

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