Gallium Selenide (GaSe) Powder and Crystals

Gallium selenide (GaSe) is a group XIII post-transitional mono-chalcogenide. Like transition metal dichalcogenides (TMDCs), it is a layered semiconductor. In gallium selenide, each individual layer consists of covalently-bonded stacks with sheets of Se ions on the top and bottom and two sheets of Ga ions in the middle.

As with other layered 2D structures like graphene, adjacent GaSe layers are bound by the weak van der Waals force. This makes it possible to peel the structure by mechanical or liquid exfoliation. The resultant ultra-thin few or single layer 2D gallium selenide nanosheets or nanoparticles have well-known nonlinear optical properties and a range of applications in areas including integrated optics, optical information communications and biology.

We supply high purity gallium selenide powder and crystals. Orders are shipped worldwide.

Gallium Selenide Powder

Can be used in electronic and optical devices and in the preparation of GaSe nanosheets or nanoparticles liquid chemical exfoliation or chemical vapour deposition

Available in quantities of 500 mg or 1 g

≥99.995% purity

From £280.00

Gallium Selenide Crystals by Size

Can be used as a semiconductor, in non-linear optics, and to produce 2D monolayer and few-layer GaSe by mechanical or liquid exfoliation

Small (>10 mm²) or medium (>25 mm²) available*

≥99.999% purity

From £480.00

*Typical representative size, areas/dimensions may vary

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Structure of Bulk and 2D Gallium Selenide

The hexagonal-layered structure of gallium selenide is similar to the structure of gallium sulfide (GaS). Each individual layer consists of four sheets of atoms in the sequence 'Se-Ga-Ga-Se'.

Each Ga atom is tetragonally-coordinated to three Se atoms and one Ga atom. Strong bonding between two sheets within the individual layer is thought to be covalent in nature, with some ionic contribution.

Depending on the sequence of stacking, the three most important classifications are β-GaSe, ε-GaSe, and γ-GaSe phases. Both β-GaSe and ε-GaSe are 2H hexagonal structured.

Bandgap and Electronic Structure

2H phase gallium selenide is semiconducting in nature, and bulk GaSe has an indirect bandgap of ~2.1 eV. Conversely, 2D GaSe thin films have a larger band gap than the bulk GaSe, and the thickness of the films has a strong influence on its electronic structure.

Optical Properties of GaSe Crystals

Gallium Selenide crystals possess wide optical transparency, ranging from the wavelength of 0.65 to 18 mm. One of the most important properties of bulk GaSe is its nonlinear optical property due to the absence of an inversion symmetric center.

Gallium Selenide Applications

GaSe has been used as a semiconductor,  photoconductor, a second harmonic generation crystal in non-linear optics, and as a far-infrared conversion material at 14-31 THz and above. GaSe also finds applications in highly-efficient solar cells and battery technology.

With excellent electrical characteristics and high photosensitivity to visible light, exfoliated ultra-thin films of gallium selenide particularly are used in electronic and optical devices such phototransistors, FETs, LEDs and photovoltaics. Non-linear optics based on GaSe have been developed in many important applications such as integrated optics, optical information communications, biology, and imaging techniques.

Gallium selenide single crystals can be used to prepare monolayer and few-layer GaSe by mechanical or liquid exfoliation. Our high-purity (>99.995%) GaSe powder enables mass production of high-quality GaSe nanosheets or nanoparticles via liquid exfoliation or chemical vapour deposition.

Synthesis of GaSe Crystals and Powder

Gallium selenide is manufactured using chemical vapour transport (CVT) crystallisation. In crystals, this yields a purity in excess of 99.999% while the powdered form has a purity in excess of 99.995%.

Processing of 2D Gallium Selenide

Viscoelastic transfer using PDMS

Literature and Reviews

Gallium Selenide Powder in Literature

• Layer-Dependent Nonlinear Optical Properties and Stability of NonCentrosymmetric Modification in Few-Layer GaSe Sheets, Angew. Chem. Int. Ed., 54, 1185 –1189 (2015); DOI: 10.1002/anie.201409837.
• Investigation of Second- and Third-Harmonic Generation in Few-Layer Gallium Selenide by Multiphoton Microscopy, L. Karvonen et al., Sci. Rep., 5:10334 (2015); DOI: 10.1038/srep10334.
• Highly sensitive phototransistor based on GaSe nanosheets, H. Huang et al., Appl. Phys. Lett. 107, 143112 (2015); doi: 10.1063/1.4933034.
• Synthesis and Photoresponse of Large GaSe Atomic Layers, S Lei, et al, Nano Lett. 2013, 13, 2777−2781 (2013)l doi: 10.1021/nl4010089.
• Red-to-Ultraviolet Emission Tuning of Two-Dimensional Gallium Sulfide/Selenide, C. Jung et al., ACS Nano., 9 (10), 9585-9593 (2015); dio: 10.1021/acsnano.5b04876.
• Shear Exfoliation and Photoresponse of 2D-Layered Gallium Selenide Nanosheets, A. Chan et al., Phys. Status Solidi RRL, 12, 1800226 (2018); DOI: 10.1002/pssr.201800226.
• Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaS Crystals with High Photoresponse, X. Li et al., Sci. Rep., 4:5497 (2014); DOI: 10.1038/srep05497.

Gallium Selenide Crystals in Literature

• Multifunctional 2D- Materials: Gallium Selenide, N. B. Singh et al., Mater. Today: Proceedings 4, 5471–5477 (2017); dio: 10.1016/j.matpr.2017.06.002.
• Effective Nonlinear GaSe Crystal Optical Properties and Applications, K. R. Allakhverdiev et al., Laser Phys., 19 (5), 1092–1104 (2009); DOI: 10.1134/S1054660X09050375.
• Copper indium gallium selenide based solar cells – a review, J. Ramanujam et al., Energy Environ. Sci., 10, 1306 (2017); DOI: 10.1039/c7ee00826k.
• Curvature-dependent flexible light emission from layered gallium selenide crystals, RSC Adv., 8, 2733 (2018); DOI: 10.1039/c7ra11600d.
• Chemical Vapor Deposition of Hexagonal Gallium Selenide and Telluride Films from Cubane Precursors: Understanding the Envelope of Molecular Control, E. Gillan et al., Chem. Mater., 9, 3037-3048 (1997); DOI: 10.1021/cm9703886.
• Morphology Control of Layer-Structured Gallium Selenide Nanowires, H. Peng et al., Nano Lett., 7 (1), 199–203 (2007); DOI: 10.1021/nl062047+.
• Size-induced effects in gallium selenide electronic structure: The influence of interlayer interactions, D. V. Rybkovskiy et al., Phys. Rev. B 84, 085314 (2011); DOI: 10.1103/PhysRevB.84.085314.