A model for photostructural changes in the amorphous AsS system

Frumar, M.; Firth, Adam; Owen, A.E.

doi:10.1016/0022-3093(83)90319-8

Cited by 59 publications

(31 citation statements)

References 3 publications

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“…So, the fraction of heteropolar As-S bonds decreases due to irradiation and, simultaneously, the fraction of homopolar As-As bonds increases in excellent agreement with known experimental evidences [7,[31][32][33][34]. Noteworthy that non-zero long-wave remainder in optical transmission difference T for unirradiated and γ-irradiated v-As 2 S 3 samples tested in direct chronology (Fig.…”

Section: Resultssupporting

confidence: 86%

“…In the first case, diamagnetic pairs of over-and under-coordinated atoms possessing an excess of positive and negative electric charges (charged defects), respectively, appear in a glassy backbone [4][5][6]. Alternatively, this process can proceed as non-defect structural transformation, provided two covalent bonds are simultaneously switched [7]. In the latter case, some kinds of impurity products can be formed preferentially at the VChS surface [5,8], the most essential being induced by interaction with absorbed oxygen, which replace chalcogen in its bonding states within glassy network.…”

Section: Introductionmentioning

confidence: 99%

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On the origin of radiation-induced metastability in vitreous chalcogenide semiconductors: The role of intrinsic and impurity-related destruction-polymerization transformations

Shpotyuk¹,

Vakiv²,

Shpotyuk³

et al. 2015

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. Radiation-optical effects in vitreous chalcogenide semiconductors are comprehensively analyzed as resulting from both intrinsic and impurity-related redistribution of covalent chemical bonds known also together as destructionpolymerization transformations. Two types of experimental measuring protocols can be used to study radiation-induced effects within ex-situ direct or in-situ backward measuring chronology, the latter being more adequate for correct separated testing of competitive inputs from both channels of destruction-polymerization transformations. Critical assessment is given on speculations trying to ignore intrinsic radiation-structural transformations in As 2 S 3 glass in view of accompanying oxidation processes. In final, this glass is nominated as the best model object among wide group of vitreous chalcogenide semiconductors revealing the highest sensitivity to radiation-induced metastability.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

On the origin of radiation-induced metastability in vitreous chalcogenide semiconductors: The role of intrinsic and impurity-related destruction-polymerization transformations

Shpotyuk¹,

Vakiv²,

Shpotyuk³

et al. 2015

Semicond. Phys. Quantum Electron. Optoelectron.

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“…In the early 80-s, this method was successfully applied to study reversible photostructural transformations in amorphous As 2 S 3 [1, 2, [15][16][17]. It was shown with account of the obtained Raman spectra that this effect is accompanied by switching of heteropolar (or heteronuclear) bonds into homopolar (or homonuclear) ones [15,16]. This method also allowed explaining the optically induced crystal-to-amorphousstate transition in As 2 S 3 as non-thermal effect probably promoted by a high density of induced defects [17].…”

Section: Introductionmentioning

confidence: 99%

Radiation-induced structural changes in chalcogenide glasses as revealed from Raman spectroscopy measurements

Kavetskyy¹

2013

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. Radiation-induced structural changes in the chalcogenide glasses of (As 2 S 3 ) x (GeS 2 ) 1-x system with x = 0.1, 0.2, 0.4, and 0.6 corresponding to the chemical compositions Ge 28.125 As 6.25 S 65.625 , Ge 23.5 As 11.8 S 64.7 , Ge 15.8 As 21 S 63.2 , and Ge 9.5 As 28.6 S 61.9 , respectively, were studied using the Raman spectroscopy technique in detail. The polarized (VV) and depolarized (VH) Raman spectra were recorded separately for two identical samples in the unirradiated and γ-irradiated states which allowed performing all measurements under the same experimental conditions. The Raman spectra were considered in the regions of high-frequency excitations related with the molecular peak, and low-frequency excitations related with the boson peak. The depolarization ratio spectra for the unirradiated and -irradiated samples were examined, too. The differential Raman spectra in the high-frequency region between unirradiated and -irradiated samples were obtained only in the VH configuration, since no spectral variations in the VV configuration were detected for all the compositions studied. Employing the differential representation ( I) and unirradiated ( R unirrad. I) samples, it has been found out that the radiation-induced structural changes are significant only for the glass composition with x = 0.4, while these changes are practically absent in the case of the glass compositions with x = 0.1, 0.2, and 0.6. The applied differential procedure allows also to detect the radiation-induced effects in clusters of corner-shared and edge-shared tetrahedral, which was not possible with IR Fast Fourier Transform spectroscopy due to different activity of IR and Raman bands. In addition, it was shown that the controversial companion c A 1 mode at 370 cm -1 to the main 340 cm -1 A 1 symmetric mode of vibrations in cornershared tetrahedra seems to be related mainly to the vibrations of edge-shared tetrahedra. The possible nanoscale structural mechanism to account for these spectral changes has been discussed.

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“…The sensitivities of conventional amorphographical techniques operating with useful information at the general background of the whole integrated signal are insufficient for this. Only in the case of amorphous a-As 2 S 3 films, the reversible photostructural transformations can be relatively simply identified as covalent-bond switching processes using Raman spectroscopy [4]. The main result of this experiment was connected only with numerical estimation of reversibly transformed bonds (near ∼6 %), while initial and finite products of covalent-bond switching (the types of destructed and newly created bonds) were not identified exactly.…”

mentioning

confidence: 89%

Photo-induced cooperative covalent-bond switching in amorphous arsenic selenide

Shpotyuk¹,

Balitska²,

Filipecki³

2005

J. Phys.: Conf. Ser.

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Abstract. A microstructural mechanism of photoinduced transformations in amorphous arsenic selenide films was studied with IR Fourier-spectroscopy technique in 300-100 cm -1 region. It was shown that stage of irreversible photostructural changes was connected with cooperative process of coordination defect formation accompanied by homopolar chemical bonds switching in heteropolar ones. On the contrary, reversible photoinduced effects were caused by heteropolar chemical bonds switching in homopolar ones, as well as additional channel of bridge heteropolar bonds switching in short-layer ones. The both processes were associated with formation of anomalously coordinated defect pairs and accompanying atomic displacements at the level of medium-range ordering. The developed mathematical simulation procedure testified in a favour of defect-related origin of the reversible photo-thermallyinduced transformations, since their kinetics corresponded to known stretched-exponential dependence, tending to bimolecular behaviour rather then to single-exponential one. IntroductionAmorphous chalcogenide semiconductors possess a unique ability to change their physical-chemical properties at the influence of external factors, first of all, the absorbed light photoexposure. These socalled photoinduced effects (PhIE) are put in the basis of xerography and lithography, CD-erasable media, memory-switching devices, photosensitive recorders, etc. [1][2][3]. Physical features of the above PhIE were well studied more than 3 decades ago, but a number of controversies concerning our understanding of their microstructural nature are still remained up to now.This situation is obviously caused by difficulties in the direct observation of local atomic structure in disordered solids. The reversible PhIE are relatively weak as they embrace no more than 10 % of atomic nodes concentration. The sensitivities of conventional amorphographical techniques operating with useful information at the general background of the whole integrated signal are insufficient for this. Only in the case of amorphous a-As 2 S 3 films, the reversible photostructural transformations can be relatively simply identified as covalent-bond switching processes using Raman spectroscopy [4]. The main result of this experiment was connected only with numerical estimation of reversibly transformed bonds (near ∼6 %), while initial and finite products of covalent-bond switching (the types of destructed and newly created bonds) were not identified exactly. Later, we showed that necessary information on the PhIE mechanism could be accurately obtained with "differential" IR Fourier spectroscopy, dealing with a part of the photoinduced spectrum, but not the whole integrated one [5]. Thus, in part, it was proved that reversible photostructural transformations in a-As 2 S 3 were explained by heteropolar As-S bonds switching in homopolar As-As and S-S ones, accompanied by simultaneous formation of specific coordination topological defects [5,6]. _____________________________

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A model for photostructural changes in the amorphous AsS system

Cited by 59 publications

References 3 publications

On the origin of radiation-induced metastability in vitreous chalcogenide semiconductors: The role of intrinsic and impurity-related destruction-polymerization transformations

On the origin of radiation-induced metastability in vitreous chalcogenide semiconductors: The role of intrinsic and impurity-related destruction-polymerization transformations

Radiation-induced structural changes in chalcogenide glasses as revealed from Raman spectroscopy measurements

Photo-induced cooperative covalent-bond switching in amorphous arsenic selenide

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