Optically induced crystal-to-amorphous-state transition in As2S3

Chalcogenide alloys can exist in both crystalline and amorphous phases, with light-induced changes between the two states. While it is generally believed that in the amorphization process light predominantly serves to melt the material that is subsequently quenched into the amorphous phase, there has been accumulating evidence, both experimental and theoretical, that photoamorphization can be athermal. In this review, we present experimental and simulational results demonstrating that both chancogenide glasses, such as pure selenium and As 50 Se 50 , and phase-change materials such as Ge 2 Sb 2 Te 5 can be rendered amorphous without going through a conventional molten phase. The ability of chalcogenides to be amorphized athermally is attributed to the presence in these materials of pronounced bonding energy hierarchy between the shorter and longer bonds.

show abstract

“…Photoamorphization has also been reported for other chalcogenides, e.g. for As 2 S 3 [11]. This process is demonstrated in Fig.…”

Section: Figurementioning

confidence: 78%

“…It was concluded that photo-amorphization of c-As 4 Se 4 occurs because of the marginal stability of the As 4 Se 4 molecular units due to the presence of the strained As-As bonds. Evolution of Raman spectra of illuminated As 2 S 3 ; the exposure time increases from curve (1) to (3), after [11] with permission from Elsevier.…”

Section: Figurementioning

confidence: 99%

Athermal amorphization of crystallized chalcogenide glasses and phase-change alloys

Kolobov

Fons

Tominaga

2013

Phys. Status Solidi B

View full text Add to dashboard Cite

show abstract

“…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]. Besides, Raman scattering measurements along with EXAFS data clearly indicated a reversible increase in the coordination number of Se in the photoexcited state due to additional dynamic bonds between pairs of overcoordinated sites [18].…”

Section: Introductionmentioning

confidence: 91%

“…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].…”

Section: Introductionmentioning

confidence: 99%

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

Kavetskyy¹

2013

Semicond. Phys. Quantum Electron. Optoelectron.

View full text Add to dashboard Cite

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.

show abstract

“…Frumar et al [26] suggested that the As 2 S 3 glass does not crystallise even after annealing for several months at temperatures near or above the glass transition temperature. These findings indicate again the high thermal stability of As 2 S 3 glass, probably because of similarities in the short range order structure and Gibbs free energy in the glassy and crystalline states of arsenic sulfide.…”

Section: C) Raman Spectra Of Annealed As 2 S 3 Doped Glassesmentioning

confidence: 99%

Spectroscopic studies of bulk AS 2 S 3 glasses and amorphous films doped with Dy, Sm and Mn

et al. 2002

View full text Add to dashboard Cite

The effect of rare earth (Dy and Sm) and transition metal (Mn) luminescent impurities on the optical properties of As 2 S 3 glass is studied in a wide spectral region. The Raman, infrared, band-to-band and edge absorption spectroscopies are employed to obtain information about the incorporation of impurity ions in the host glass structure and the corresponding changes in intrinsic optical characteristics. The effects of light-soaking and thermal treatment on the doped As 2 S 3 glasses were examined as well. In the fundamental absorption region a reflectivity maximum at 2.98 eV shows blue (Dy, Sm) or red (Mn) shift depending on the electronegativity of the impurity, in accordance with the corresponding variations of the glass structure. Near the edge absorption the impurity affects strongly the slope and the magnitude of the weak absorption tail. In the wide range of transparency the addition of impurity suppresses several absorption bands indicating the interaction of dopants with the host glass contaminations. Some variations of the characteristic Raman spectra under light exposure and thermal ageing of doped glasses were registered. The observed effects of metal dopants on the As 2 S 3 glass are discussed in connection with the expected behaviour of the impurities in the glass.

show abstract

Optically induced crystal-to-amorphous-state transition in As2S3

Cited by 48 publications

References 13 publications

Athermal amorphization of crystallized chalcogenide glasses and phase-change alloys

Athermal amorphization of crystallized chalcogenide glasses and phase-change alloys

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

Spectroscopic studies of bulk AS 2 S 3 glasses and amorphous films doped with Dy, Sm and Mn

Contact Info

Product

Resources

About