Defects in TlGaSe2

Гусейнов, Г. Г.; Aliyev, Vügar; Bagirzade, E. F.

doi:10.1016/0254-0584(85)90004-5

Cited by 9 publications

(13 citation statements)

References 11 publications

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“…The excessive concentrations of cation vacancies create favourable conditions for the formation of creep dislocations, causing spiral twisting. The investigations of the forms and numbers of inclusions in TlGaSe 2 [24] have led to the conclusion that there are linear defects in which segregation of impurities takes place. The segregation of super-stoichiometric selenium may follow the similar way.…”

Section: Resultsmentioning

confidence: 99%

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Study of optical absorption in TlGaSe2:Zn2+ single crystals

Makhnovets¹,

Myronchuk²,

Піскач³

et al. 2018

Ukr. J. Phys. Opt.

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Abstract. We report the results of experimental studies for the optical absorption in TlGaSe 2 :Zn 2+ single crystals grown using a modified Bridgman-Stockbarger technique. The absorption measurements at different temperatures are performed with the steps 50 K. The analysis of the experimental data yield in the absorption coefficients of TlGaSe 2 :Zn varying from 20 to 800 cm -1 in the temperature region 100-300 K. Direct and indirect bandgap values for TlGaSe 2 :Zn 2+ are calculated as functions of temperature. These values are respectively equal to 2.22 and 2.04 eV at 100 K. It is revealed that the spectral dependences of the absorption coefficient in the region 60-130 cm -1 follow the Urbach rule, whereas the corresponding steepness parameter and the Urbach energy increase with increasing temperature.

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Section: Resultsmentioning

confidence: 99%

“…[24], the TlGaSe 2 crystals usually deviate significantly from the stoichiometry conditions. The deficits of thallium and gallium are respectively 1.54 and 1.12 at.…”

Section: Resultsmentioning

confidence: 99%

Study of optical absorption in TlGaSe2:Zn2+ single crystals

Makhnovets¹,

Myronchuk²,

Піскач³

et al. 2018

Ukr. J. Phys. Opt.

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“…In the case of undoped (pristine) TlGaSe 2 bulk-layered compounds, the selenium vacancies are energetically preferable to the other kinds of native defects [92][93][94][95][96][97][98][99][100]. Intrinsic chalcogen vacancies are an unavoidable key defects of undoped TlGaSe 2 samples.…”

Section: ( ) E T G Dmentioning

confidence: 99%

Modification of the optical and elastic properties of TlGaSe₂ layered semiconductor produced by the memory effect

Cengiz,

Gören,

Sönmez

et al. 2023

Phys. Scr.

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A comparative analysis of the temperature behaviors of optical and elastic properties of TlGa Se 2 single crystals under a memory effect experimental condition are presented for the first time. A memory effect condition suggests that the sample is thermally annealed inside the incommensurate (INC) phase for a time interval the corresponding physical parameters is measured experimentally. From ultrasound velocity measurements, carried out before and after the thermal annealing process subjected to the sample, the noticeable changes in the temperature variation of the longitudinal ultrasonic wave velocity associated with the elastic constants C 33 of TlGa Se 2 due to the memory effect was detected. Our results reveal that thermal annealing performed at the INC - phase has some influence on the optical absorption of TlGa Se 2 crystals in the visible spectral region. We assumed that thermal annealing within INC - phase is accompanied with the appearance, inside TlGa Se 2 samples, a new quasiperiodic frozen structure formed from the intrinsic defects migrated into the lowest energy diffusion barriers of the INC - modulation wave. Such structural modulation is incommensurate with the underlying lattice of TlGa Se 2 and can lead to changes in the electronic band structure and the optical bandgaps of TlGa Se 2 .

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“…[ 7–19 ] The electrical conduction perpendicular to the layers is expected to be highly sensitive to inevitable structural defects such as: planar defects presented between the layers due to a slipping of successive layers, point defects, charged impurities, deep level traps, dislocations as well as to many other crystal lattice imperfections that are mainly attributed to the interlayer stacking faults. [ 20–22 ] Only at extremely high temperatures, due to the thermally activated free carriers from the valence band the intrinsic electrical conduction is determined by a band‐to‐band mechanism.…”

Section: Introductionmentioning

confidence: 99%

A Study of Thermoelectric Performance of TlGaSe₂ Layered Dichalcogenides from First‐Principles Calculations: Vacancy Defects Modeling and Engineering

Çaydaşı

Mintaş

Chumakov

et al. 2021

Physica Status Solidi (b)

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Herein, the thermoelectric performance of TlGaSe2 ternary layered dichalcogenides is evaluated by applying ab initio density functional theory calculations combined with Boltzmann's transport equation. A novel approach to design the intrinsic structural defects via Se‐anion vacancies in unit cell has been developed. Two kinds of Se‐vacancy defects in host TlGaSe2 crystal lattice are engineered: the single vacancy defect induced intrinsically in the unit cell (1×1×1) and in the supercell lattice (1×1×4). It is found that the electrical transport properties and thermoelectric efficiency of this semiconductor could be significantly altered by introducing Se‐vacancy states into crystalline structure. In addition, simulation shows that inclusion of Se‐vacancy defects significantly improves the thermoelectric efficiency as well as the thermoelectric power factor and figure of merit (ZT) values of this compound. Additionally, the thermoelectric performance of TlGaSe2 is estimated by means of the electronic fitness function calculations in the valence and conduction edges. The results demonstrate that TlGaSe2 with introduced Se‐vacancies may be a perspective material for thermoelectric applications.

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Defects in TlGaSe2

Cited by 9 publications

References 11 publications

Study of optical absorption in TlGaSe2:Zn2+ single crystals

Study of optical absorption in TlGaSe2:Zn2+ single crystals

Modification of the optical and elastic properties of TlGaSe₂ layered semiconductor produced by the memory effect

A Study of Thermoelectric Performance of TlGaSe₂ Layered Dichalcogenides from First‐Principles Calculations: Vacancy Defects Modeling and Engineering

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Defects in TlGaSe2

Cited by 9 publications

References 11 publications

Study of optical absorption in TlGaSe2:Zn2+ single crystals

Study of optical absorption in TlGaSe2:Zn2+ single crystals

Modification of the optical and elastic properties of TlGaSe2 layered semiconductor produced by the memory effect

A Study of Thermoelectric Performance of TlGaSe2 Layered Dichalcogenides from First‐Principles Calculations: Vacancy Defects Modeling and Engineering

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Product

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Modification of the optical and elastic properties of TlGaSe₂ layered semiconductor produced by the memory effect

A Study of Thermoelectric Performance of TlGaSe₂ Layered Dichalcogenides from First‐Principles Calculations: Vacancy Defects Modeling and Engineering