Gallium Sulfide (GaS) Powder and Crystals

Gallium sulfide (GaS) is a layered semiconductor and it belongs to group XIII post-transitional mono-chalcogenide. In gallium sulfide each individual layer consists of covalently-bonded S−Ga−Ga−S stacks with sheets of S ions on the top and bottom and two sheets of Ga ions in the middle.

Unlike GaSe and many other monochalcogenides, bulk GaS (α-GaS phase) possesses a much larger indirect band gap of ∼2.6 eV, with the potential to increases up to more than 3.0 eV by decreasing film thickness due to quantum confinement effects. Therefore, 2D GaS is believed to fill the the gap between 2D small-band-gap semiconductors and insulators.

Hexagonal (2H phase) β-GaS is the energetically favourable crystal arrangement among the four GaS polytypes. Like all other layered 2D structures, adjacent GaS layers are bound by the weak van der Waals force along the c-axis. This makes it possible to peel the structure by mechanical or liquid exfoliation. The resultant ultra-thin few or single layer 2D gallium sulfide nanosheets or nanoparticles can be employed in innovative photoelectrochemical (PEC)-type UV-selective photodetectors for medical diagnostics, air purification, chemical analysis, and advanced optical communication system.

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

Gallium Sulfide Powder

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

Available in quantities of 500 mg or 1 g

≥99.995% purity

From £350.00

Gallium Sulfide Crystals by Size

Can be used as a semiconductor, in photoelectrochemical cells, and to produce 2D monolayer and few-layer GaS by mechanical or liquid exfoliation

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

≥99.999% purity

From £800.00

*Typical representative size, areas/dimensions may vary.

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Structure of Bulk and 2D Gallium Sulfide

Gallium sulfide (GaS) has a hexagonal-layered structure. Each individual layer consists of four sheets of atoms in the sequence 'S-Ga-Ga-S'.

Each Ga atom is tetragonally-coordinated to three S 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 two most important classifications are α-GaS and β-GaS. Both α-GaS and β-GaS are hexagonal structured.

Bandgap and Electronic Structure

2H phase gallium sulfide is semiconducting in nature, and bulk GaS has an indirect bandgap of ~2.59 eV. Conversely, 2D GaS thin films have a larger band gap than the bulk GaS, and the thickness of the films has a strong influence on its electronic properties.

Bulk GaS bandgap is decreased by 0.4 - 0.6 eV in comparison to that of bilayer.

Properties of Gallium Sulfide

• Yellow in appearance
• Hexagonal structure with layers bonded by Van der Waals forces
• Layers consist of sheets of covalently bonded atoms in the sequence S-Ga-Ga-S
• Thickness dependant indirect bandgap of ~2.59 eV and a direct gap of 3.05 eV

More information is available on the properties tab.

Gallium Sulfide Applications

Gallium sulfide can be used in the preparation of mono and few-layer GaS, nanosheets and nanoparticles. Due to its semiconducting and non-linear optical properties, it has a wide range of largely under-exploited applications.

These include:

• Solar cells
• Photodetectors
• Sensors
• Hydrogen evolution catalysts

GaS has been used as a semiconductor,  photodetector and hydrogen evolution catalysts. GaSe also finds applications in tandem solar photoelectrochemical cells in combination with other visible-sensitive low bandgap materials for PEC solar energy conversion application.

2D GaS has also been explored for applications in transistors, energy storage, gas sensing, optoelectronics and and nonlinear optics.

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

Synthesis of GaS Crystals and Powder

Gallium sulfide 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 Sulfide

Viscoelastic transfer using PDMS

Literature and Reviews

• Two-Dimensional Gallium Sulfide Nanoflakes for UV Selective Photoelectrochemical-type Photodetectors, M. Zappia et al., J. Phys. Chem. C, 125, 11857−11866 (2021); DOI: 10.1021/acs.jpcc.1c03597.
• Preparation of Gallium Sulfide Nanosheets by Liquid Exfoliation and Their Application As Hydrogen Evolution Catalysts, A. Harvey et al., Chem. Mater. 2015, 27, 3483−3493 (2015); DOI: 10.1021/acs.chemmater.5b00910.
• Large-Area Growth and Stability of Monolayer Gallium Monochalcogenides for Optoelectronic Devices, T. Afaneh et al., ACS Appl. Nano Mater. 3, 8, 7879–7887 (2020); DOI: 10.1021/acsanm.0c01369.
• Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals, B. Carey et al., Nat. Commun., 8 14482 (2017); DOI: 10.1038/ncomms14482.
• Vapor-Liquid-Solid Growth and Optoelectronics of Gallium Sulfide van der Waals Nanowires, E. Sutter et al., ACS Nano, 14, 5, 6117–6126 (2020); DOI: 10.1021/acsnano.0c01919.