DLTS Study of Pd-H Complexes in Si

2012 ◽  
Vol 725 ◽  
pp. 213-216
Author(s):  
Sunao Abe ◽  
Ryuichi Goura ◽  
Koichi Shimoe ◽  
Yoichi Kamiura ◽  
Yoshifumi Yamashita ◽  
...  
Keyword(s):  
Conduction Band ◽  
Energy Levels ◽  
Annealing Behavior ◽  
Electron Traps

We have observed five electron traps with energy levels at 0.16, 0.30, 0.40, 0.53 and 0.67 eV below the conduction band in Pd and H doped Si by DLTS technique. Successive annealing at 373 K and 473 K for 30 min respectively caused two levels at Ec-0.16 eV and Ec-0.67 eV to disappear and simultaneously a new level to emerge at Ec-0.19 eV. From such annealing behavior and the comparison of the energy levels observed in the present study with those in the literature, we assign them to various Pd and H related defects as follows, Pd-H2: Ec-0.16 eV and Ec-0.67 eV, Pd acceptor: Ec-0.19 eV, Pd-H3: Ec-0.30 eV, Pd-H1: Ec-0.40 eV.

Photon-induced deactivations of multiple traps in CH3NH3PbI3 perovskite films by different photon energies

2021 ◽  
Author(s):  
Asmida Herawati ◽  
Hui-Ching Lin ◽  
Shun-Hsiang Chan ◽  
Ming-Chung Wu ◽  
Tsong-Shin Lim ◽  
...  
Keyword(s):  
Conduction Band ◽  
Energy Levels ◽  
Conduction Band Minimum ◽  
The Other ◽  
Electron Traps

Two types of electron traps were identified in MAPbI3 perovskite; one can be deactivated by 633 nm and 405 nm illuminations, whereas the other one only by 405 nm illumination. The energy levels of both traps were beneath the conduction band minimum.

Passivation and Depassivation of Interface Traps at the SiO2/4H-SiC Interface by Potassium Ions

2012 ◽  
Vol 717-720 ◽  
pp. 761-764 ◽  
Author(s):  
Pétur Gordon Hermannsson ◽  
Einar Ö. Sveinbjörnsson
Keyword(s):  
Thermal Stability ◽  
Conduction Band ◽  
Energy Levels ◽  
Sample Surface ◽  
Conduction Band Edge ◽  
Potassium Ions ◽  
Interface Traps ◽  
Bias Stress ◽  
Dry Oxidation ◽  
Thermal Stability Of

We investigate the passivation of interface traps by method of oxidizing Si-face 4H-SiC in the presence of potassium as well as examining the thermal stability of this passivation process. It is observed that this type of dry oxidation leads to a strong passivation of interface traps at the SiO2/4H-SiC interface with energy levels near the SiC conduction band edge. Furthermore, it is observed that if potassium ions residing at the SiO2/SiC interface are moved towards the sample surface by exposing them to ultraviolet light (UV) under an applied depletion bias stress at high temperatures the interface traps become electrically active again and are evidently depassivated. These findings are in line with recently a published model of the effect of sodium on such interface states

scholarly journals Doped TiO2: the effect of doping elements on photocatalytic activity

2020 ◽  
Vol 1 (5) ◽  
pp. 1193-1201 ◽  
Author(s):  
Anna Khlyustova ◽  
Nikolay Sirotkin ◽  
Tatiana Kusova ◽  
Anton Kraev ◽  
Valery Titov ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Conduction Band ◽  
Energy Levels ◽  
Doped Tio2 ◽  
New Energy ◽  
Effect Of Doping

Doping of TiO2 with various elements increases its photocatalytic activity due to the formation of new energy levels near the conduction band.

scholarly journals Optical properties of SrF2 and SrF2:Ce3+ crystals codoped with In3+

RSC Advances ◽  
2020 ◽  
Vol 10 (24) ◽  
pp. 13992-13997
Author(s):  
Alexandra Myasnikova ◽  
Roman Shendrik ◽  
Alexander Bogdanov
Keyword(s):  
Optical Properties ◽  
Conduction Band ◽  
Luminescence Center ◽  
Electron Traps

In3+ states are located close to electron traps and have a band character, the transfer of electrons from conduction band to the luminescence center is possible without significant trapping which facilitates fast luminescence in SrF2:Ce3+,In3+.

Note on the contact between a metal and an insulator or semi-conductor

1938 ◽  
Vol 34 (4) ◽  
pp. 568-572 ◽  
Author(s):  
N. F. Mott
Keyword(s):  
Quantum Mechanics ◽  
Conduction Band ◽  
Stationary State ◽  
Energy Levels ◽  
Electronic Energy ◽  
Thermal Agitation ◽  
Metallic Crystal ◽  
Electronic Energy Levels

According to quantum mechanics there exists in any non-metallic crystal a band of allowed electronic energy levels which are unoccupied when the crystal is in its state of lowest energy. We call this band the conduction band; the crystal can conduct electricity if electrons are raised into the conduction level from lower levels. According to the theory of semi-conductors given by Wilson, there exist in these substances lattice imperfections at which an electron can exist in a bound stationary state below the conduction band, electrons being raised from these levels into the conduction band by the thermal agitation of the surrounding atoms.

Photocatalysis of NaYF4:Yb,Er/CdSe composites under 1560 nm laser excitation

RSC Advances ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 8127-8133 ◽  
Author(s):  
Xingyuan Guo ◽  
Changfeng Chen ◽  
Daqi Zhang ◽  
Carl P. Tripp ◽  
Shengyan Yin ◽  
...  
Keyword(s):  
Valence Band ◽  
Conduction Band ◽  
Laser Excitation ◽  
Energy Levels

Upon 1560 nm excitation, higher energy levels of Er3+ ions are populated. FRET and photons reabsorption to occur from NaYF4:Yb,Er to CdSe. Then activated CdSe produces electrons and holes in the conduction band and the valence band, respectively.

scholarly journals The mean free path of electrons in polar crystals

1939 ◽  
Vol 171 (947) ◽  
pp. 496-504 ◽  
Keyword(s):  
Free Path ◽  
Conduction Band ◽  
Thermal Energy ◽  
Low Temperatures ◽  
Energy Levels ◽  
Stoichiometric Composition ◽  
Mean Free Path ◽  
Polar Crystals ◽  
Absorption Of Light ◽  
The Mean

Polar crystals of stoichiometric composition at low temperatures are insulators of electricity. If, however, electrons are raised into the normally empty conduction band of energy levels, either through the absorption of light or the thermal energy of surrounding atoms, the crystal can conduct. The purpose of this note is to calculate the mean free path of such electrons, and hence their mobility (velocity of drift in unit field). The results obtained will be compared with experimental material obtained from semi-conductors and from substances which show photoconductivity.

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.

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