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Bishop, S. G.; Shevchik, N. J.

doi:10.1103/physrevb.12.1567

Cited by 119 publications

(28 citation statements)

References 28 publications

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“…A strong repulsion between As and S/Se s levels due to chemical ordering is more likely to be responsible for the separation of the s band into high ͑As͒ and low ͑S/Se͒ subbands. 39 Note that the two s subbands are perfectly separated only when the chemical ordering is perfect, i.e., in models with all-heteropolar bonds, as seen in Figs. 8͑d͒ and 8͑e͒.…”

Section: Electronic Structurementioning

confidence: 92%

Simulation of physical properties of the chalcogenide glassAs2S3using a density-functional-based tight-binding method

et al. 2004

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We have used a density-functional-based tight-binding method in order to create structural models of the canonical chalcogenide glass, amorphous As 2 S 3 . The models range from one containing defects that are both chemical ͑homopolar bonds͒ and topological ͑valence-alternation pairs͒ in nature to one that is defect-free ͑stoichiometric͒. The structural, vibrational, and electronic properties of the simulated models are in good agreement with experimental data where available. The electronic densities of states obtained for all models show clean optical band gaps. A certain degree of electron-state localization at the band edges is observed for all models, which suggests that photoinduced phenomena in chalcogenide glasses may not necessarily be attributed to the excitation of defects of only one particular kind.

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Section: Electronic Structurementioning

confidence: 92%

Simulation of physical properties of the chalcogenide glassAs2S3using a density-functional-based tight-binding method

et al. 2004

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“…According to band structure calculations in a tight-binding approximation [13,14], the states near the valence band edge of As 2 S 3 result predominantly from the p-orbital electron lone-pair of the chalcogen atom (low-energy side of the reflectivity peak in Fig.2), and the high-energy side of the peak is due to p-and -orbital states of chalcogen. In addition to chalcogen orbitals, both parts contain contributions of the p-and s-orbitals of arsenic.…”

Section: Uv-vis Reflectivity Spectra In the Fundamental Absorption Rementioning

confidence: 99%

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

et al. 2002

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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.

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“…A combination of the photoemission spectra with tightbinding calculations, using the known crystal structures, strongly suggests that exactly this type of bonding occurs in the crystals of several archetypal chalcogenides: As 2 S 3 , As 2 Se 3 , and As 2 Te 3 . 49 In Table II, we compile data on the deviation from the ideal octahedral coordination and the corresponding ppσ transfer integrals, in several distinct compositions and stoichiometries characteristic of common chalcogenide and pnictide alloys. One observes that a high value of t ′ σ /t σ is indeed characteristic of ppσ-bonded materials, whereby the angular deviation from the ideal coordination does not exceed 10 • .…”

Section: Ppσ-bonded Semiconductors: the Role Of The Secondary Ppσmentioning

confidence: 99%

Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. I. The formation of the ppσ-network

Zhugayevych

Lubchenko

2010

The Journal of Chemical Physics

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Semiconductor glasses exhibit many unique optical and electronic anomalies. We have put forth a semi-phenomenological scenario (J. Chem. Phys. 132, 044508 (2010)) in which several of these anomalies arise from deep midgap electronic states residing on high-strain regions intrinsic to the activated transport above the glass transition. Here we demonstrate at the molecular level how this scenario is realized in an important class of semiconductor glasses, namely chalcogen and pnictogen containing alloys. Both the glass itself and the intrinsic electronic midgap states emerge as a result of the formation of a network composed of σ-bonded atomic p-orbitals that are only weakly hybridized. Despite a large number of weak bonds, these ppσ-networks are stable with respect to competing types of bonding, while exhibiting a high degree of structural degeneracy. The stability is rationalized with the help of a hereby proposed structural model, by which ppσ-networks are symmetry-broken and distorted versions of a high symmetry structure. The latter structure exhibits exact octahedral coordination and is fully covalently-bonded. The present approach provides a microscopic route to a fully consistent description of the electronic and structural excitations in vitreous semiconductors.

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Densities of valence states of amorphous and crystallineAs2S3,<

Cited by 119 publications

References 28 publications

Simulation of physical properties of the chalcogenide glassAs2S3using a density-functional-based tight-binding method

Simulation of physical properties of the chalcogenide glassAs2S3using a density-functional-based tight-binding method

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

Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. I. The formation of the ppσ-network

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