scholarly journals Theoretical study of intraband optical transitions in conduction band of dot-in-a-well system

AIP Advances ◽  
2014 ◽  
Vol 4 (2) ◽  
pp. 027125 ◽  
Author(s):  
Venkata R. Chaganti ◽  
Vadym Apalkov
Keyword(s):  
Conduction Band ◽  
Theoretical Study ◽  
Optical Transitions

INTRABAND AUGER EFFECT IN QUANTUM DOT STRUCTURES

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2872-2878
Author(s):  
T. GEBHARD ◽  
K. UNTERRAINER ◽  
D. ALVARENGA ◽  
P. S. S. GUIMARAES ◽  
J. M. VILLAS-BOAS ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Conduction Band ◽  
Theoretical Calculations ◽  
Optical Transitions ◽  
Auger Process ◽  
Final State ◽  
Auger Effect ◽  
Absorption Measurements

Intraband photocurrent and absorption measurements were performed on InAs / InGaAlAs / InP quantum dot structures. To identify the optical transitions, theoretical calculations were performed and showed that the observed PC is generated by a bound to bound transition, where the final state is about 200 meV deep below the conduction band continuum. The reported results strongly suggest that an Auger process plays a fundamental role in generating the observed intraband photocurrent.

scholarly journals Experimental and theoretical study of polarization-dependent optical transitions in InAs quantum dots at telecommunication-wavelengths (1300-1500 nm)

2011 ◽  
Vol 109 (10) ◽  
pp. 104510 ◽  
Author(s):  
Muhammad Usman ◽  
Susannah Heck ◽  
Edmund Clarke ◽  
Peter Spencer ◽  
Hoon Ryu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Theoretical Study ◽  
Optical Transitions ◽  
Inas Quantum Dots

scholarly journals Mechanism of luminescence and efficient energy storage in Lu2SiO5 : Ce3+single crystals

2020 ◽  
Vol 23 (3) ◽  
pp. 177-185
Author(s):  
V. A. Tedzhetov ◽  
A. V. Podkopaev ◽  
A. A. Sysoev
Keyword(s):  
Single Crystals ◽  
Conduction Band ◽  
High Energy ◽  
Energy Structure ◽  
Optical Transitions ◽  
Thermally Stimulated Luminescence ◽  
Excitation Energies ◽  
Absorption Bands ◽  
Electron Traps ◽  
Extrinsic Absorption

The development of high energy physics and medicine has raised the necessity of heavy stintillating materials with a large total gamma quantum absorption cross-section, high quantum output and fast response. Cerium doped lutetium silicate Lu2SiO5 : Ce3+ (LSO) has high density, large effective atomic number and high conversion efficiency. In this work we have reported optical absorption spectroscopy and photoluminescence data for LSO single crystals grown using the modified Musatov method. The absorption spectra show the fundamental intrinsic absorption edge of Lu2SiO5 at ~200 nm and four extrinsic absorption bands of Ce3+ activator near 250—375 nm. The band gap is 6.19 to 6.29 eV depending on optical beam direction. We have confirmed that the extrinsic absorption bands correspond to optical transitions in Ce3+ activator ions localized in two crystallographically non-equivalent CeI and CeII positions. We have estimated that oscillator force for the optical transitions in Ce3+ ions. The photoluminescence spectra excited by 3.49 eV photon energy UV laser contain three bands: ~2.96 eV, ~3.13 eV (CeI) and ~2.70 eV (CeII). The energy structure of electron traps in LSO has been studied with thermally stimulated luminescence, the crystals being exposed to UV with different spectral and energy parameters. All the experimental thermally stimulated luminescence curves contain at least two peaks at 345 and 400 K with a 4 : 1 intensity ratio attributable to electron traps at 0.92—0.96 and1.12—1.18 eV. LSO exposure to high pressure mercury lamp radiation having the highest energy has for the first time showed the presence of traps at 0.88 eV. A model of the energy structure of LSO has been developed. The luminescence mechanism in the material is more complex than purely intracenter one. We show that high excitation energies may lead to ionization by the mechanism hva + Ce3+ = Ce4+ + e-. We have assumed that the storage of excitation energy involves not only Ce3+ activator but also the conduction band as well as trap states localized near the conduction band.

INFLUENCE OF OPTICAL EXCITATION OF TWO-DIMENSIONAL SURFACE SUBBANDS ON PHOTOCURRENT ACROSS SEMICONDUCTOR–ELECTROLYTE INTERFACE

1997 ◽  
Vol 04 (05) ◽  
pp. 933-935 ◽  
Author(s):  
H. L. MARGARIAN ◽  
V. A. MELICKSETIAN ◽  
V. M. AROUTIOUNIAN
Keyword(s):  
Valence Band ◽  
Conduction Band ◽  
Optical Excitation ◽  
Optical Transitions ◽  
Two Dimensional ◽  
Electrolyte Interface ◽  
Dimensional Surface

It was shown that in the case of TiO 2 contacted with an electrolyte, optical transitions of electrons from the valence band to the two-dimensional surface subband located near the conduction band or covered with the band.

Formation mechanism and spectroscopy of C6H radicals in extreme environments: a theoretical study

2019 ◽  
Vol 21 (41) ◽  
pp. 23044-23055 ◽  
Author(s):  
Chih-Hao Chin ◽  
Tong Zhu ◽  
John Zeng Hui Zhang
Keyword(s):  
Gas Phase ◽  
Formation Mechanism ◽  
Spectral Region ◽  
Theoretical Study ◽  
Extreme Environments ◽  
Optical Transitions ◽  
Franck Condon

Franck–Condon calculations of C6H radical predict optical transitions in the spectral region of a gas phase.

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