First principle investigation into hexagonal and cubic structures of Gallium Selenide

Ghalouci, L.; Benbahi, B.; Hiadsi, S.; Abidri, B.; Vergoten, Gérard; Ghalouci, F.

doi:10.1016/j.commatsci.2012.08.034

Cited by 40 publications

(31 citation statements)

References 67 publications

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“…It is worth noticing that the sole use of GGA‐PBE96 to describe exchange‐correlation interaction between the electrons underestimates the material E g (around ≈1 eV), since it neglects the screened Coulomb potential for Hartree–Fock exchange . By contrast, the use of hybrid HSE06 functionals ( Figure a) results in an E g of 1.91 eV, which is similar to experimental values reported in literature (between 1.9 and 2.0 eV) . By reducing the number of layers in the GaSe, the E g progressively increases up to the highest value in 1L‐GaSe (see Figure S1, Supporting Information), i.e., 2.19 eV with the GGA‐PBE96 and 3.14 eV with HSE06 (Figure b).…”

Section: Resultssupporting

confidence: 83%

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Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

Zappia

Bianca

Bellani

et al. 2020

Adv Funct Materials

106

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Gallium selenide (GaSe) is a layered compound, which has been exploited in nonlinear optical applications and photodetectors due to its anisotropic structure and pseudodirect optical gap. Theoretical studies predict that its 2D form is a potential photocatalyst for water splitting reactions. Herein, the photoelectrochemical (PEC) characterization of GaSe nanoflakes (single‐/few‐layer flakes), produced via liquid phase exfoliation, for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in both acidic and alkaline media is reported. In 0.5 m H2SO4, the GaSe photoelectrodes display the best PEC performance, corresponding to a ratiometric power‐saved metric for HER (Φsaved,HER) of 0.09% and a ratiometric power‐saved metric for OER (Φsaved,OER) of 0.25%. When used as PEC‐type photodetectors, GaSe photoelectrodes show a responsivity of ≈0.16 A W−1 upon 455 nm illumination at a light intensity of 63.5 µW cm−2 and applied potential of −0.3 V versus reversible hydrogen electrode (RHE). Stability tests of GaSe photodetectors demonstrated a durable operation over tens of cathodic linear sweep voltammetry scans in 0.5 m H2SO4 for HER. In contrast, degradation of photoelectrodes occurred in both alkaline and anodic operation due to the highly oxidizing environment and O2‐induced (photo)oxidation effects. The results provide new insight into the PEC properties of GaSe nanoflakes for their exploitation in photoelectrocatalysis, PEC‐type photodetectors, and (bio)sensors.

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Section: Resultssupporting

confidence: 83%

“…Due to the pseudodirect gap behavior of GaSe, n was set equal to 2. The estimated E g is 1.9 eV, as the one measured for GaSe crystals . Ultraviolet photoelectron spectroscopy (UPS) measurements were performed to determine the Fermi level energy (E F ), i.e., the WF, and the E VBM , of the GaSe flakes .…”

Section: Resultsmentioning

confidence: 99%

Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

Zappia

Bianca

Bellani

et al. 2020

Adv Funct Materials

106

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“…Gallium selenide (GaSe) is a typical kind of layered metal monochalcogenides, which has a direct band gap energy of ∼2 eV (see Ref. 22) and generally exhibits p-type behavior. 23,24 A single layer of GaSe is composed of covalently bonded Se-Ga-Ga-Se atoms, with the lattice constant 3.74Å and D 3h symmetry.…”

Section: Introductionmentioning

confidence: 99%

Mechanical stabilities and nonlinear properties of monolayer Gallium selenide under tension

et al. 2015

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The mechanical stabilities and nonlinear properties of monolayer Gallium selenide (GaSe) under tension are investigated by using density functional theory (DFT). The ultimate stresses and ultimate strains and the structure evolutions of monolayer GaSe under armchair (AC), zigzag (ZZ) and equiaxial (EQ) tensions are predicted. A thermodynamically rigorous continuum description of nonlinear elastic response is given by expanding the elastic strain energy density in a Taylor series in Lagrangian strain truncated after the fifth-order term. Fourteen nonzero independent elastic constants are determined by least-square fit to the DFT calculations. Pressure-dependent elastic constants (C ij (P )) and pressure derivatives of C ij (P ) (C ij ) are also calculated. Calculated values of ultimate stresses and strains and the in-plane Young's modulus are all positive. It proves that monolayer GaSe is mechanically stable.

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“…Our result of the bulk modulus is close to what has been theoretically reported for ε-InSe (44.39 GPa), β-InSe (44.16 GPa) and ε-GaSe (49.62 GPa). 65,95 .…”

Section: Elastic Constantsmentioning

confidence: 99%

Electronic structure, lattice dynamics, and optical properties of a novel van der Waals semiconductor heterostructure: InGaSe2

et al. 2017

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There is a growing interest in the property dependence of transition metal dichalcogenides as function of the number of layers and formation of heterostructures. Depending on the stacking, doping, edge effects and interlayer distance, the properties can be modified, which open the door to novel applications which require a detailed understanding of the atomic mechanisms responsible for those changes. In this work, we analyze the electronic properties and lattice dynamics of a heterostructure constructed by simultaneously stacking InSe layers and GaSe layers bounded by van der Waals forces. We have assumed the same space group of GaSe, P6m2 as it becomes the lower energy configuration for other considered stackings. The structural, vibrational and optical properties of this layered compound have been calculated using density functional theory. The structure is shown to be energetically, thermally and elastically stable, which indicates its possible chemical synthesis. A correlation of the theoretical physical properties with respect to its parent compounds is extensively discussed. One of the most interesting properties is the low thermal conductivity, which indicates its potential use in thermolectric applications. Additionally, we discuss the possibility of using electronic gap engineering methods, which can help into tune the optical emission in a variable range close to that used in the field of biological systems (NIR). Finally, the importance of considering properly van der Waals dispersion in layered materials has been emphasized as included in the exchange correlation functional. As for the presence of atoms with important spin orbit coupling, relativistic corrections have been included.

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First principle investigation into hexagonal and cubic structures of Gallium Selenide

Cited by 40 publications

References 67 publications

Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

Mechanical stabilities and nonlinear properties of monolayer Gallium selenide under tension

Electronic structure, lattice dynamics, and optical properties of a novel van der Waals semiconductor heterostructure: InGaSe2

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