Electron traps in CdS single crystals obtained by admittance spectroscopy on the hetero- and Schottky junctions

1979 ◽  
Vol 18 (4) ◽  
pp. 345-352 ◽  
Author(s):  
A. Kobayashi ◽  
T. Mori
Keyword(s):  
Single Crystals ◽  
Admittance Spectroscopy ◽  
Electron Traps ◽  
Schottky Junctions

Investigation of relation between Ga concentration and defect levels of Al/Cu(In,Ga)Se2 Schottky junctions using admittance spectroscopy

2007 ◽  
Vol 515 (15) ◽  
pp. 6208-6211 ◽  
Author(s):  
T. Sakurai ◽  
N. Ishida ◽  
S. Ishizuka ◽  
K. Matsubara ◽  
K. Sakurai ◽  
...  
Keyword(s):  
Admittance Spectroscopy ◽  
Defect Levels ◽  
Schottky Junctions

Deep-Level Defects in Nitrogen-Doped 6H-SiC Grown by PVT Method

2008 ◽  
Vol 1069 ◽  
Author(s):  
Pawel Kaminski ◽  
Michal Kozubal ◽  
Krzysztof Grasza ◽  
Emil Tymicki
Keyword(s):  
Single Crystals ◽  
Defect Structure ◽  
Deep Level ◽  
Nitrogen Concentration ◽  
Activation Energies ◽  
Electron Traps ◽  
Nitrogen Doped ◽  
Significant Change

ABSTRACTAn effect of the nitrogen concentration on the concentrations of deep-level defects in bulk 6H-SiC single crystals is investigated. Six electron traps labeled as T1A, T1B, T2, T3, T4 and T5 with activation energies of 0.34, 0.40, 0.64, 0.67, 0.69, and 1.53 eV, respectively, were revealed. The traps T1A (0.34 eV) and T1B (0.40 eV), observed in the samples with the nitrogen concentration ranging from ∼2×1017 to 5×1017 cm−3, are attributed to complexes formed by carbon vacancies located at various lattice sites and carbon antisites. The concentrations of traps T2 (0.64 eV) and T3 (0.67 eV) have been found to rise from ∼5×1015 to ∼1×1017 cm−3 with increasing the nitrogen concentration from ∼2×1017 to ∼2.0×1018 cm−3. These traps are assigned to complexes involving silicon vacancies occupying hexagonal and quasi-cubic sites, respectively, and nitrogen atoms. The trap T4 (0.69 eV) concentration also substantially rises with increasing the nitrogen concentration and it is likely to be related to complexes formed by carbon antisites and nitrogen atoms. The midgap trap T5 (1.53 eV) is presumably associated with vanadium contamination. The presented results show that doping with nitrogen involves a significant change in the defect structure of 6H-SiC single crystals.

Characterization of Defects in N-Type 6H-SiC Single Crystals by Optical Admittance Spectroscopy

1994 ◽  
Vol 339 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel
Keyword(s):  
Transition Metal ◽  
Single Crystals ◽  
Admittance Spectroscopy ◽  
Donor Atom ◽  
Deep Defect ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
Defect Levels ◽  
Type Conduction

ABSTRACTOptical admittance spectroscopy is a technique for measuring the conductance and capacitance of a junction under illumination as a function of the wavelength of the light and the frequency of the measuring AC signal. This technique has been applied to characterize deep defect levels in 6H-SiC:N. Nitrogen is a donor atom in 6H-SiC which substitutes for carbon in three inequivalent sites (h, k1, k2). giving rise to n-type conduction. Deep defect levels attributable to transition metal impurities have also been identified in 6H-SiC:N. We have examined persistent photoconductance in this material by optical admittance spectroscopy.

Electron Traps in Rutile TiO2 Crystals: Intrinsic Small Polarons, Impurities, and Oxygen Vacancies

2015 ◽  
Vol 1731 ◽  
Author(s):  
Larry E. Halliburton
Keyword(s):  
Single Crystals ◽  
Ground State ◽  
Oxygen Vacancies ◽  
Laser Light ◽  
Large Family ◽  
Electron Traps ◽  
Bulk Single Crystals ◽  
State Models ◽  
Small Polarons ◽  
Trapped Electron

ABSTRACTRutile TiO2 is well known for its ability to “trap” photoinduced electrons at Ti4+ ions and form Ti3+ ions with an unpaired d1 electron. This has been shown experimentally to result in a large family of similar, yet slightly different, Ti3+-related centers that include both intrinsic small polarons and donor-bound small polarons. In these latter centers, the Ti3+ ion is located next to an oxygen vacancy or an impurity such as fluorine, lithium, or hydrogen. These small polarons are easily formed in commercially available bulk single crystals of rutile TiO2 by illuminating oxidized (and nominally undoped) samples at temperatures between 5 and 30 K with sub-band-gap laser light (e.g., 442 nm) or by slight reducing treatments (in the case of hydrogen). Once formed, the ground states of the defects are readily studied at low temperature with magnetic resonance (EPR and ENDOR). Single crystals of rutile TiO2 provide complete sets of angular dependence data, and thus allow detailed information about the ground-state models of the electron traps to be extracted in the form of g matrices and hyperfine matrices. In this review, the differences and similarities of the various Ti3+-related trapped electron centers are described.

Photoinduced admittance spectroscopy to detect the shallow electron traps in nitrogen-doped highly compensated ZnSe

1997 ◽  
Vol 81 (5) ◽  
pp. 2425-2428 ◽  
Author(s):  
Fang Lu ◽  
Shouqi Wang ◽  
Hyundon Jung ◽  
Ziqiang Zhu ◽  
Takafumi Yao
Keyword(s):  
Admittance Spectroscopy ◽  
Electron Traps ◽  
Nitrogen Doped

Schottky junctions on perovskite single crystals: light-modulated dielectric constant and self-biased photodetection

2016 ◽  
Vol 4 (35) ◽  
pp. 8304-8312 ◽  
Author(s):  
Parvez A. Shaikh ◽  
Dong Shi ◽  
Jose Ramon Duran Retamal ◽  
Arif D. Sheikh ◽  
Md. Azimul Haque ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Single Crystals ◽  
Hybrid Perovskite ◽  
Schottky Junctions

Schottky-junctions formed on hybrid perovskite CH3NH3PbBr3 single crystals show significant light-induced tuning of dielectric constant and self-biased photodetection.

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.

Deep level transient spectroscopy of electron traps and sensitizing centers in undoped CdS single crystals

1981 ◽  
Vol 52 (1) ◽  
pp. 261-268 ◽  
Author(s):  
M. Hussein ◽  
G. Lleti ◽  
G. Sagnes ◽  
G. Bastide ◽  
M. Rouzeyre
Keyword(s):  
Single Crystals ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Electron Traps ◽  
Transient Spectroscopy
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