Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe Crystals with High Photoresponse

Li, Xufan; Lin, Ming; Puretzky, Alexander A.; Idrobo, Juan Carlos; Ma, Cheng; Chi, Miaofang; Yoon, Mina; Rouleau, Christopher M.; Kravchenko, Ivan I.; Geohegan, David B.; Xiao, Kai

doi:10.1038/srep05497

Cited by 243 publications

(274 citation statements)

References 50 publications

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“…4,5 In the monolayer limit, GaSe exhibits a direct-to-indirect band gap transition, and therefore shows an opposite trend to the thickness dependence in most transition metal dichalcogenides. 6,7 As the number of layers is decreased below seven layers, the shape of the valence band close to its maximum at the Γ point undergoes a change and develops a Mexican hat or caldera-like inverted plateau 6,8,9 as shown in Fig. 1b.…”

Section: Introductionmentioning

confidence: 98%

Large-grain MBE-grown GaSe on GaAs with a Mexican hat-like valence band dispersion

et al. 2018

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Atomically thin GaSe has been predicted to have a non-parabolic, Mexican hat-like valence band structure due to the shift of the valence band maximum (VBM) near the Γ point which is expected to give rise to novel, unique properties such as tunable magnetism, high effective mass suppressing direct tunneling in scaled transistors, and an improved thermoelectric figure of merit. However, the synthesis of atomically thin GaSe remains challenging. Here, we report on the growth of atomically thin GaSe by molecular beam epitaxy (MBE) and demonstrate the high quality of the resulting van der Waals epitaxial films. The full valence band structure of nominal bilayer GaSe is revealed by photoemission electron momentum microscopy (k-PEEM), confirming the presence of a distorted valence band near the Γ point. Our results open the way to demonstrating interesting new physical phenomena based on MBE-grown GaSe films and atomically thin monochalcogenides in general.

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Section: Introductionmentioning

confidence: 98%

Large-grain MBE-grown GaSe on GaAs with a Mexican hat-like valence band dispersion

et al. 2018

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“…As presented by review studies [3][4][5][6][7], when a layered material is thinned from bulk to monolayer, it can exhibit enhanced and different physical properties. Post-transition-metal chalcogenides (PTMCs) are important examples of such vdW layered materials having the chemical formula MX where M stands for post-transition metal and X for chalcogenide atom [8][9][10][11]. GaS and GaSe are two emerging members of PTMCs.…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of monolayer GaS and GaSe crystals

et al. 2016

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The mechanical properties of monolayer GaS and GaSe crystals are investigated in terms of their elastic constants: in-plane stiffness (C), Poisson ratio (ν), and ultimate strength (σ U ) by means of first-principles calculations. The calculated elastic constants are compared with those of graphene and monolayer MoS 2 . Our results indicate that monolayer GaS is a stiffer material than monolayer GaSe crystals due to the more ionic character of the Ga-S bonds than the Ga-Se bonds. Although their Poisson ratio values are very close to each other, 0.26 and 0.25 for GaS and GaSe, respectively, monolayer GaS is a stronger material than monolayer GaSe due to its slightly higher σ U value. However, GaS and GaSe crystals are found to be more ductile and flexible materials than graphene and MoS 2 . We have also analyzed the band-gap response of GaS and GaSe monolayers to biaxial tensile strain and predicted a semiconductor-metal crossover after 17% and 14% applied strain, respectively, for monolayer GaS and GaSe. In addition, we investigated how the mechanical properties are affected by charging. We found that the flexibility of single layer GaS and GaSe displays a sharp increase under 0.1e/cell charging due to the repulsive interactions between extra charges located on chalcogen atoms. These charging-controllable mechanical properties of single layers of GaS and GaSe can be of potential use for electromechanical applications.

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“…There are other forms of metal chalcogenides that are equally intriguing. Among these is the C-M-M-C family, which has been drawing more attention [8,9]. These materials have been used to produce photocatalysts, photo-detectors, image sensors, and transistors with high electron mobility [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Atomic Layer Growth of InSe and Sb2Se3 Layered Semiconductors and Their Heterostructure

et al. 2017

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Abstract:Metal chalcogenides based on the C-M-M-C (C = chalcogen, M = metal) structure possess several attractive properties that can be utilized in both electrical and optical devices. We have shown that specular, large area films of γ-InSe and Sb 2 Se 3 can be grown via atomic layer deposition (ALD) at relatively low temperatures. Optical (absorption, Raman), crystalline (X-ray diffraction), and composition (XPS) properties of these films have been measured and compared to those reported for exfoliated films and have been found to be similar. Heterostructures composed of a layer of γ-InSe (intrinsically n-type) followed by a layer of Sb 2 Se 3 (intrinsically p-type) that display diode characteristics were also grown.

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Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe Crystals with High Photoresponse

Cited by 243 publications

References 50 publications

Large-grain MBE-grown GaSe on GaAs with a Mexican hat-like valence band dispersion

Large-grain MBE-grown GaSe on GaAs with a Mexican hat-like valence band dispersion

Mechanical properties of monolayer GaS and GaSe crystals

Atomic Layer Growth of InSe and Sb2Se3 Layered Semiconductors and Their Heterostructure

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