Effects of sulfur isotopic composition on the band gap of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>PbS</mml:mi></mml:mrow></mml:math>

Lian, H. J.; Yang, A.; Thewalt, M. L. W.; Lauck, R.; Cardona, M.

doi:10.1103/physrevb.73.233202

Cited by 29 publications

(23 citation statements)

References 20 publications

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“…It can be found in nature and also grown as an n-or p-type semiconductor with carrier concentrations as low as 10 17 cm −3 . Its small electronic gap (0.4 eV), with an anomalous temperature dependence [2], implies small effective masses which make PbS useful as a material for nanostructures [3]. On the negative side, it is a visually offensive black product which appears during the degradation of lead white pigment in artwork [4].…”

Section: Introductionmentioning

confidence: 99%

Temperature‐dependent Raman scattering of natural and isotopically substituted PbS

Etchegoin

Cardona

Lauck

et al. 2008

Physica Status Solidi (b)

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Lead sulfide is an important semiconductor that has found technological applications for over a century. Raman spectroscopy, a standard tool for the investigation and characterization of semiconductors, has limited application to this material because of the forbidden nature of its first order scattering and its opacity to visible lasers. Nevertheless, useful vibrational spectra from two-phonon processes are obtained with red lasers, probably because of a resonance in the concomitant electronic transitions. Here we report temperature dependent spectra, covering the 10-300 K range, for two samples with different sulfur isotopic compositions. The results are analyzed by comparison with ab initio calculations of the lattice dynamics of PbS and the corresponding densities of one and two-phonon states. Emphasis is placed on the analysis of the two phonon band centered at ∼ 430 cm −1 .

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Section: Introductionmentioning

confidence: 99%

Temperature‐dependent Raman scattering of natural and isotopically substituted PbS

Etchegoin

Cardona

Lauck

et al. 2008

Physica Status Solidi (b)

Self Cite

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“…In bulk semiconductors, the variation of the band gap as a function of the temperature is direct consequence of the renormalization of the band gap via the electron-phonon interaction and of the thermal expansion of the lattice. 42 In the framework of the two-oscillator model [43][44][45][46] , the band gap E g is approximated by…”

Section: 2425mentioning

confidence: 99%

Excitons in atomically thin black phosphorus

et al. 2016

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Raman scattering and photoluminescence spectroscopy are used to investigate the optical properties of single layer black phosphorus obtained by mechanical exfoliation of bulk crystals under an argon atmosphere. The Raman spectroscopy, performed in situ on the same flake as the photoluminescence measurements, demonstrates the single layer character of the investigated samples. The emission spectra, dominated by excitonic effects, display the expected in plane anisotropy. The emission energy depends on the type of substrate on which the flake is placed due to the different dielectric screening. Finally, the blue shift of the emission with increasing temperature is well described using a two oscillator model for the temperature dependence of the band gap.Black phosphorus, the most stable of all the allotropes of phosphorus, has been intensively studied by different experimental methods from the early fifties of the last century.1-7 Bulk black phosphorus is a semiconductor, with a band gap of about 0.335 eV.1,4 The orthorombic bulk crystal has a layered structure, with atomic layers bound by weak van der Waals interactions. A single atomic layer is puckered, with the phosphorus atoms being parallel in the (010) plane. 3,8,9 Atomically thin monolayers have been recently isolated using mechanical exfoliation, 10 adding black phosphorus to the rapidly growing family of emerging two dimensional materials. The band gap of black phosphorus is always direct and can be tuned from 0.3 eV to the nearly visible part of the spectrum 11,12 . In contrast, graphene is gapless, 13 and the transition metals dichalcogenides (TMDs) have an indirect gap in bulk phase and only monolayer TMDs have a direct gap.14 Moreover, black phosphorus exhibits a strong in-plane anisotropy 11,12,[15][16][17] , absent in graphene and TMDs. Additionally, the relatively high mobilities measured at room temperature combined with the direct band gap result in an on/off ratio for FET transistors of the order of 10 5 . 26 The exciton binding energy and consequently the emission energy strongly depend on the dielectric environment (substrate) 10,27 . This could partially explain the wide range of values for the black phosphorus emission energy found in the literature, possibly related also to a slightly different composition of the SiO 2 substrates employed. Moreover, owing to the limited life time of the samples, the various characterization techniques used to identify monolayer black phosphorus (e.g. atomic force microscopy, Raman spectroscopy) could not always be performed on the same flake where the optical response was investigated.In this paper we present a systematic investigation of the optical properties of monolayers of black phosphorus. We analyze the properties of the emission as a function of the dielectric constant of the substrate, excitation power, polarization and temperature. The single layer character of the investigated flakes is demonstrated using in situ Raman measurements on the same flake used for the PL. We show that the PL emission ...

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“…The energy tolerance was 2.0 × 10 − 5 eV/atom, the force tolerance was 0.05 eV/Å, and the displacement tolerance was 0.002 Å. Valence electron configurations considered in the study were S 3s 2 3p 4 , Pb 5d 10 6s 2 6p 2 , Ag 4d 10 5s 1 , Zn 3d 10 4s 2 , Cu 3d 10 4s 1 , In 4d 10 5s 2 5p 1 , Sb 5s 2 5p 3 , Tl 5d 10 6s 2 6p 1 , Mn 3d 5 4s 2 , As 4s 2 4p 3 , Cd 4d 10 5s 2 and Bi 6s 2 6p 3 states. International Journal of Mineral Processing 98 (2011) 132-136 Galena (PbS) crystallizes in the rocksalt structure (Lian et al, 2006), which consists of equal numbers of lead and sulfur ions placed at alternate points of a simple cubic lattice, in such a way that each ion has six of the other kind of ions as its nearest neighbors. The space group is Fm3m with a cell parameter of a = 5.936 Å, Z = 4 (Wright et al, 1999).…”

Section: Methodsmentioning

confidence: 99%