Luminescence of exciton in GeS

Senske, W.; Street, R. A.; Nowitzki, A.; Wiesner, P.

doi:10.1016/0022-2313(78)90079-0

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…The polarization-dependent µPL and µRaman spectra of a multilayer GeS with thickness about 40 nm are shown in is unique in polarization-dependent PL emission for a thin multilayer GeS at 300 K. A Si-doped bulk GeS also revealed a similar radiation of E||a at 1.7 K. [21] This result can verify our room-temperature polarized µPL result of the thin multilayer GeS in Figure 2a. The selection rule of the BE-PL emission can be attributed to the transition dipole moment along the a or b axis of the multilayer GeS.…”

Section: Doi: 101002/adom201600814supporting

confidence: 81%

Polarized Band‐Edge Emission and Dichroic Optical Behavior in Thin Multilayer GeS

2016

Advanced Optical Materials

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1 of 6) 1600814and optical absorption behaviors of GeS nanosheets have been studied and proposed for energy applications, [16,17] however, the light-emitting property of a thin multilayer GeS was not yet explored.Herein, in-plane optical anisotropy of band-edge emission of a multilayer GeS stripe (t ≈ 40 nm) is characterized by using polarized micro-photoluminescence (µPL) measurement with polarization angles ranging from 0 to 90° with respect to the multilayer's longest crystal edge (b axis). Light emission from multilayer GeS is completely forbidden at θ = 0° (E||b), and fully allowed (intense light) at θ = 90° (E||a), which obeys a dichroic Malus law [18] for the emission peak at 1.622 eV. Multilayer GeS behaves like a dichroic light emitter with linear polarization along the multilayer's a axis. To understand the band-edge characteristic of the GeS multilayer, polarized thermoreflectance (PTR) measurement by using microscope white-light guiding was also implemented. The selection rule of the PTR spectra also reveals that the lower band-edge transition E A = 1.622 eV is only allowed with E||a polarization while another higher energy transition, E B = 1.732 eV, appears merely along the E||b polarization in the multilayer. In-plane anisotropy of the c plane GeS multilayer occurs with linear polarization along a and b axes. The energy position of the E A transition matches well with the main band-edge emission observed by µPL, while the E B transition may probably originate from valence-band splitting (dominated by the S p orbital) of the multilayer GeS. The structural and optical anisotropy of the multilayer GeS is discussed here.Layered single crystals of IV-VI GeS with different areas, sizes, and thicknesses were grown by using the chemical vapor transport (CVT) method [19] with iodine as the transport agent. The crystals were prepared from their elements (Ge: 99.999% pure and S: 99.999%) by reaction at 600 °C for two days in evacuated quartz ampoules. Sulfur was added in 1 mol% excess with respect to the stoichiometric mixture of the constituent elements. About 10 g of the elements, together with an appropriate amount of transport agent (I 2 about 10 mg cm −3 ), were introduced into a quartz ampoule (22 mm OD, 17 mm ID, 20 cm length), which was then cooled with liquid nitrogen, evacuated to 10 −6 Torr and sealed. The mixture was slowly heated to 600 °C and maintained at this temperature for two days. The temperature was then altered from 600 °C (heating zone) → 520 °C (growth zone) with a gradient of -4 °C cm −1 for crystal growth. The reaction was left 240 h to produce large single crystals. The as-grown GeS crystals are dark red and have a shiny surface with an area of up to 5 mm 2 and thickness of up to 100 µm. The crystals are mostly like ribbon or stripe-shape layered crystals (see Figure S1 in the Supporting Information). The powder and single-crystal X-ray diffraction (XRD) results of GeS shown in Figure S1 reveal an orthorhombic phase. The lattice constants are a = 4.36 Å, b = 3.67 Å, and c = 10.53 Å,

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Section: Doi: 101002/adom201600814supporting

confidence: 81%

Polarized Band‐Edge Emission and Dichroic Optical Behavior in Thin Multilayer GeS

2016

Advanced Optical Materials

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“…The localised states in these crystals can arise from the presence of defects and impurities. Bletskan et al [26] and Senske et al [27] did in fact observe impurity and trapping levels of a great variety in the band gap of G e S crystals. Also Karakostas [28] observed that extended planar defects, mainly growth twins and twist low angle boundaries producing typical dislocation networks affected the electrical properties of G e S .…”

Section: Discussionmentioning

confidence: 97%

High pressure studies on layered semiconductor germanium sulphide single crystals grown using different techniques

Solanki

Patel

Agarwal

et al. 2001

High Pressure Research

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“…This allows for modulation of its emission wavelength. [32][33][34][35][36] GeS also exhibits high photosensitivity, a broad spectral response, and giant piezoelectricity because of its characteristic "puckered" symmetry. 25,27,37 Analogously to BP, the low symmetry orthorhombic crystal structure of GeS results in unique anisotropic optical, electronic, and vibrational properties along the zigzag (ZZ) and armchair (AC) axes, 35,[38][39][40][41] which makes it suitable for large-scale applications in photovoltaic thermoelectric 42 and optoelectronics.…”

Section: Introductionmentioning

confidence: 99%

Optical properties of orthorhombic germanium sulfide: unveiling the anisotropic nature of Wannier excitons

Arfaoui,

Zawadzka,

Ayari

et al. 2023

Nanoscale

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Luminescence of exciton in GeS

Cited by 9 publications

References 8 publications

Polarized Band‐Edge Emission and Dichroic Optical Behavior in Thin Multilayer GeS

Polarized Band‐Edge Emission and Dichroic Optical Behavior in Thin Multilayer GeS

High pressure studies on layered semiconductor germanium sulphide single crystals grown using different techniques

Optical properties of orthorhombic germanium sulfide: unveiling the anisotropic nature of Wannier excitons

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