scholarly journals The features of deformation-stimulated RbI luminescence

2021 ◽  
Vol 5 (4) ◽  
pp. 218-228
Author(s):  
L. N. Myasnikova ◽  
A. G. Maratova ◽  
K. Sh. Shunkeyev
Keyword(s):  
Elastic Deformation ◽  
Thermal Activation ◽  
Spectral Composition ◽  
Activation Energies ◽  
Luminescence Spectra ◽  
Radiation Defects ◽  
Thermally Stimulated Luminescence ◽  
Radiative Relaxation ◽  
Interstitial Atoms

This paper studies deformation-stimulated features of radiative relaxation of self-trapped excitons and recombination assembly of exciton-like luminescence in RbI crystal. Methods of research were luminescence and thermal activation spectroscopy. The identity of the mechanism of manifestation of the X-ray luminescence, tunnel luminescence and thermally stimulated luminescence spectra were found in the elastically deformed RbI crystal, interpreted by the luminescence of self-trapped exciton, tunnel recharge of F′, VK -pairs and thermally stimulated recombination of e−, VK -centres, respectively.The temperatures of the maximum destruction peaks of thermally stimulated luminescence, their spectral composition and activation energies were determined experimentally, on the basis of which the mechanisms of recombination assembly of exciton-like luminescences in a RbI crystal were interpreted. Uniaxial elastic deformation leads to the effective formation of point radiation defects ( F′, HA, VK -centers) in comparison with an unbroken lattice, where the predominant mechanism is the association of interstitial atoms ( H -centres) with the formation of I3−-centres.

scholarly journals Radiation defects in NaCl matrix with reduced lattice symmetry caused by light cation doping and elastic uniaxial deformation

2021 ◽  
Vol 61 (3) ◽  
Author(s):  
K. Shunkeyev ◽  
Zh. Ubaev ◽  
A. Lushchik ◽  
L. Myasnikova
Keyword(s):  
Elastic Deformation ◽  
Elastic Stress ◽  
Electronic Excitations ◽  
Uniaxial Deformation ◽  
Thermally Stimulated Luminescence ◽  
Absorption Bands ◽  
Radiative Relaxation ◽  
X Ray ◽  
Lattice Symmetry ◽  
Subsequent Thermal Annealing

The processes of radiation defect creation and radiative relaxation of electronic excitations under applied local or/and uniaxial elastic deformation have been studied in NaCl crystals by means of optical absorption, luminescence and thermoactivation spectroscopy methods. In NaCl:Li at 80 K, X-ray-induced absorption bands peaked around 3.35 and 4.6 eV have been detected and ascribed to interstitial halide atoms located nearby Li impurity cations, HA(Li) centres. Subsequent thermal annealing of HA(Li) centres leads to the formation of polyhalide centres responsible for the absorption band at 5.35 eV. In an X-irradiated and stressed NaCl:Li crystal (degree of uniaxial elastic deformation of ε = 0.9%), the peak of thermally stimulated luminescence at ~115 K is composed of the ~2.7-eV emission appearing, in our opinion, due to the recombination of the electron, thermally released from an F′ centre, with a hole-type HA(Li) centre. The applied uniaxial elastic stress facilitates the self-trapping of anion excitons in regular regions of a NaCl lattice and impedes the energy transfer by mobile excitons to impurities/defects and, in turn, attenuates the Br-related luminescence peaked at 3.95 eV with respect to the π-emission of self-trapped excitons (~3.35 eV). The 3.95 eV emission has been detected in a natural NaCl crystal containing homologous Br impurity ions.

Estimates for Diffusion Barriers and Atomic Potentials in Mgo: Cndo/2 Calculations for the Study of Microwave Effects in Sintering

1990 ◽  
Vol 189 ◽  
Author(s):  
L. Skala ◽  
V.M. Kenkre ◽  
M.W. Weiser ◽  
J.D. Katz
Keyword(s):  
Microwave Sintering ◽  
Activation Energies ◽  
Diffusion Barriers ◽  
Electron Densities ◽  
Self Consistent ◽  
Interstitial Atoms ◽  
Microwave Effects

ABSTRACTAs part of a program of investigation of microwave sintering, self-consistent CNDO/2 calculations are presented for diffusion barriers and potentials for the motion of interstitial atoms and vacancies in MgO. Clusters of 30 atoms are used in the calculations. Activation energies, diffusion barriers, shape of the potentials and electron densities are obtained.

Thermal activation energies of Mg in GaN:Mg measured by the Hall effect and admittance spectroscopy

2000 ◽  
Vol 88 (5) ◽  
pp. 2564-2569 ◽  
Author(s):  
D. J. Kim ◽  
D. Y. Ryu ◽  
N. A. Bojarczuk ◽  
J. Karasinski ◽  
S. Guha ◽  
...  
Keyword(s):  
Hall Effect ◽  
Thermal Activation ◽  
Activation Energies ◽  
Admittance Spectroscopy

The neutron irradiation effects on the temperature dependencies of the electrical conductivity of nanosilicon particles

2017 ◽  
Vol 31 (28) ◽  
pp. 1750257 ◽  
Author(s):  
Elchin Huseynov ◽  
Aydan Garibli
Keyword(s):  
Electrical Conductivity ◽  
Neutron Flux ◽  
Neutron Irradiation ◽  
Silicon Nanoparticles ◽  
Activation Energies ◽  
Radiation Defects ◽  
Irradiation Effects ◽  
Active Radiation ◽  
Before And After ◽  
Effects Of Temperature

The effects of temperature and neutron irradiation on the silicon nanoparticles have been studied at different frequencies. It has been defined that additional electro-active radiation defects occur in the silicon nanomaterial after neutron irradiation. Therefore, the change of neutron flux at the interval of [Formula: see text]–[Formula: see text] increases the conductivity of nanosilicon. Activation energies of the silicon nanoparticles were calculated for 10 different constant frequencies according to Arrhenius approach before and after neutron irradiation. The mechanism of electrical conductivity which explains results has been established.

Thermal Activation Energies for the Three Inequivalent Lattice Sites for the BSi Acceptor in 6H-SiC

1997 ◽  
Vol 258-263 ◽  
pp. 691-696 ◽  
Author(s):  
A.O. Evwaraye ◽  
S.R. Smith ◽  
W.C. Mitchel ◽  
H. McD. Hobgood ◽  
G. Augustine ◽  
...  
Keyword(s):  
Thermal Activation ◽  
Activation Energies

Characterization of Semi-insulating SiC

2006 ◽  
Vol 911 ◽  
Author(s):  
Nguyen Tien Son ◽  
Patrick Carlsson ◽  
Björn Magnusson ◽  
Erik Janzén
Keyword(s):  
Vapor Deposition ◽  
Thermal Activation ◽  
Deep Level ◽  
Chemical Vapor ◽  
Activation Energies ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

AbstractElectron paramagnetic resonance was used to study defects in high-purity semi-insulating (HPSI) substrates grown by high-temperature chemical vapor deposition and physical vapor transport. Deep level defects associated to different thermal activation energies of the resistivity ranging from ~0.6 eV to ~1.6 eV in HPSI substrates are identified and their roles in carrier compensation processes are discussed. Based on the results obtained in HPSI materials, we discuss the carrier compensation processes in vanadium-doped SI SiC substrates and different activation energies in the material.

Behavior of Deep Defects After Hydrogen Passivation in Znte Studied by Photoluminescence and Photoconductivity

1998 ◽  
Vol 510 ◽  
Author(s):  
S. Bhunia ◽  
D.N. Bose
Keyword(s):  
Thermal Activation ◽  
Hydrogen Plasma ◽  
Minority Carrier Lifetime ◽  
Activation Energies ◽  
Band Edge ◽  
Band Edge Emission ◽  
Hydrogen Passivation ◽  
Deep Acceptor ◽  
Strong Band ◽  
Deep Acceptor Level

AbstractThe effects of hydrogen passivation in undoped p-ZnTe single crystals were studied by photoluminescence (PL) and photoconductivity (PC) measurements. Samples were exposed to r.f hydrogen plasma at 250 °C for different durations. Before passivation PL peaks were observed at 2.06 eV, 1.47 eV, 1.33 eV and 1.06 eV. After 60 minutes exposure, samples showed strong band edge green luminescence at 2.37 eV due to an exciton bound to a Cu acceptor. Further exposure to plasma resulted in disappearance of 2.37eV and 2.34 eV peaks due to damage. In PC studies the dark current was found to decrease by a factor of 70 on 60 minutes passivation. From the temperature dependence of PC gain, the minority carrier lifetime τn, was found to go through a maximum of 4.5 × 10−7 sec at 220 K before passivation. After 60 minutes exposure, τn, remained constant at 4.5 × 10−7 sec for T > 220 K and decreased for T < 220 K. The activation energies of τn, were determined and show marked changes on passivation for T > 220 K. Comparison between PL and PC studies showed that the deep acceptor level OTe responsible for emission at 2.06 eV is passivated giving rise to strong band edge emission at 2.37 eV while emission due to the midgap impurity levels at 1.47, 1.33 and 1.05 eV remained unaffected. The thermal activation energies of the PL peaks have also been determined and allow the construction of a defect energy level diagram for ZnTe.

scholarly journals Электрически активные состояния захвата и переноса заряда, обусловливающие медленную рекомбинацию в кристаллах бромида таллия при низких температурах

2018 ◽  
Vol 52 (2) ◽  
pp. 171
Author(s):  
В. Кажукаускас ◽  
Р. Гарбачаускас ◽  
С. Савицки
Keyword(s):  
Activation Energy ◽  
Electric Field ◽  
Single Crystals ◽  
Applied Electric Field ◽  
Thermal Activation ◽  
Thermal Quenching ◽  
Activation Energies ◽  
Trap States ◽  
Optical Generation ◽  
Stockbarger Method

AbstractTlBr single crystals grown by the Bridgman–Stockbarger method are studied. It is established that frozen-conductivity effects manifest themselves under interband excitation by light at temperatures below 200 K. Herewith, clearly pronounced superlinear dependences of the induced photoconductivity on the strength of the applied electric field manifest themselves. The results of studying thermally stimulated conductivity evidence that these phenomena can be associated with the filling of trap states with thermal activation energies of 0.08–0.12 eV. This state can be removed due to thermal quenching at temperatures of ≳180 K because of the emptying of energy states with an activation energy of 0.63–0.65 eV filled after optical generation.

Sign in / Sign up

Export Citation Format

Share Document