Germanium Selenide (GeSe) Powder and Crystal

Germanium selenide (GeSe) belongs to the Group IV layered metal mono-chalcogenides. It has a puckered layer structure similar to that of black phosphorus (BP). However, unlike BP, each germanium cation is triple-coordinated with a lone electron pair pointing to the inter-layer spacing. The lone electron pair thus is subject to inter-layer coupling to enhance the binding force between layers. 

The high quality of TMDC monolayers have mostly been fabricated by mechanical and chemical exfoliations from bulk crystals or high-purity powders. However, few-to-monolayer GeSe films with direct bandgaps are still hard to obtain by mechanical exfoliation due to the high fragility of GeSe mono-crystalline flakes. Liquid-phase exfoliation of high-purity powders is an alternative way to prepare GeSe nanosheets or nanoparticles.

Germanium Selenide (GeSe) Powder from Ossila was used in the high-impact paper (IF 11.19), γ-GeSe: A New Hexagonal Polymorph from Group IV–VI Monochalcogenides, S. Lee et al., Nano Lett. 21, 4305–4313 (2021); DOI: 10.1021/acs.nanolett.1c00714.

The strong covalent bonds within the layer but weak van der Waals interactions between the layers leads to the elimination of dangling bonds and surface states, which provides chemically-inert surfaces and considerably high chemical and environmental stability. So unlike phosphorene, devices based on GeSe provide greater stability and resistance to oxidation.

GeSe is the only Group IV mono-chalcogenide (MX) that has a direct bandgap. It has closely-placed direct and indirect bandgaps that overlap well with the solar spectrum, making it a potential material for photovoltaic and photodetecting applications. Germanium selenide (GeSe) is also the most attractive group IV chalcogenide due to its structural robustness, with isotropic lithiation kinetics and high rate capability. 

GeSe is also earth-abundant and environmentally-friendly, which makes it a particularly attractive candidate for applications like semiconductors. Out of its five free-standing polymorph forms, β-GeSe, γ-GeSe, δ-GeSe and ε-GeSe are indirect gap semiconductors, whereas α-GeSe is not.

We supply low price Germanium selenide in several different forms for a range of applications.

Germanium Selenide Powder

Can be used for preparation of germanium selenide nanoplates and ultrathin films

Sold by weight

≥99.995% purity

From £200

Germanium Selenide Crystals by Size

Can be used to produce single or few-layer germanium selenide sheets via mechanical or liquid exfoliation

Small (≥10 mm²) or medium (≥25 mm²) crystals available*

≥99.999% purity

From £480

*Typical representative size, areas/dimensions may vary

Bulk single Germanium selenide crystal is most commonly used as sources from which single or few-layer sheets can be obtained via either mechanical or liquid exfoliation. 

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Germanium selenide powder can also be used to prepare GeSe nanosheets and nanoparticles by liquid-exfoliation (normally assisted by sonication). 

Key Product Data

• High purity, low price Germanium selenide
• Available as a powder or as individual crystals
• Can be used to produce single or few-layer sheets
• Free worldwide shipping on qualifying orders

Structure of Germanium Selenide

Germanium selenide (GeSe) belongs to the Group IV layered metal mono-chalcogenides. It has a similar structure to phosphorene, and crystallises in a highly anisotropic layered orthorhombic (distorted NaCl-type) crystal structure with Pnma symmetry. Each primitive unit cell of the orthorhombic crystal structure contains eight atoms organised in adjacent double-puckered layers. The atoms in each double puckered layer bond to their three nearest neighbours by covalent bonds and form a zigzag chain along the direction of the minor axis of the crystal.

Properties of Germanium Selenide

After exfoliation of crystals or powder, germanium selenide typically has the following properties:

• Group IV layered metal mono-chalcogenides
• Puckered layer structure similar to that of black phosphorus.
• Orthorhombic (distorted NaCl-type) crystal structure (Space group Pnma)
• Chemically-inert surfaces and considerably high chemical and environmental stability
• Closely-placed direct and indirect bandgaps that overlap well with the solar spectrum

Germanium Selenide Applications

Germanium selenide single crystals can be used to prepare monolayer and few-layer GeSe by mechanical or liquid exfoliation. Germanium Selenide powder is suitable for liquid chemical exfoliation to prepare GeSe nanosheets and nanoparticles down to few-layer films. 

Germanium Selenide is a promising semiconductor for electronic and opto-electronic applications (such as photovoltaics, phototransistors, thermoelectrics, and energy storage devices.

Germanium selenide is a p-type semiconductor with closely-located direct and indirect band gaps in the range of 1.1 – 1.2 eV. GeSe also exhibits a high absorption coefficient of ~105 cm⁻¹ in the visible range and a high hole mobility of 128.6 cm² V⁻¹ s⁻¹, making it a promising semiconductor for electronic and opto-electronic applications (such as photovoltaics, phototransistors, thermoelectrics, and energy storage devices.

The GeSe layered structure with strongly-pronounced anisotropy of physical properties is a promising material for the manufacturing of photodetectors, lasers in the near-infrared range, thermo-electric, high-capacity lithium ion batteries, and photovoltaic devices.

Processing Germanium Selenide

Viscoelastic transfer using PDMS

Literature and Reviews

• Electronic structure of germanium selenide investigated using ultra-violet photoelectron spectroscopy, P Mishra et al., Semicond. Sci. Technol., 30, 075001 (2015); doi:10.1088/0268-1242/30/7/075001.
• Structural and electronic properties of atomically thin germanium selenide polymorphs, S. Zhang et al., Sci China Mater., 58: 929–935 (2015); doi: 10.1007/s40843-015-0107-5.
• Layered material GeSe and vertical GeSe/MoS2 p-n heterojunctions, W. Yap et al., Nano Res., 11(1): 420–430 (2018); doi: 10.1007/s12274-017-1646-8.
• Germanium and Tin Selenide Nanocrystals for High-Capacity Lithium Ion Batteries: Comparative Phase Conversion of Germanium and Tin, H. Im et al., J. Phys. Chem. C, 118, 21884−21888 (2014); dio: 10.1021/jp507337c.
• Short-Wave Near-Infrared Linear Dichroism of Two-Dimensional Germanium Selenide, X. Wang etal., J. Am. Chem. Soc., 139, 14976-14982 (2017); DOI: 10.1021/jacs.7b06314.
• Temperature induced phonon behaviour in germanium selenide thin films probed by Raman spectroscopy, J. Phys. D: Appl. Phys., 49, 315301 (2016); doi:10.1088/0022-3727/49/31/315301.
• Band Structure and Photoelectric Characterization of GeSe Monolayers, H. Zhao et al., Adv. Funct. Mater., 28, 1704855 (2018); DOI: 10.1002/adfm.201704855.
• Nanocomb Architecture Design Using Germanium Selenide as High- Performance Lithium Storage Material, H. Kim et al., Chem. Mater., 28, 6146−6151 (2016); DOI: 10.1021/acs.chemmater.6b02016.
• GeSe monolayer semiconductor with tunable direct band gap and small carrier effective mass,  Y. Hu et al., Appl. Phys. Lett. 107, 122107 (2015); doi: 10.1063/1.4931459.
• Two-Dimensional GeSe as an Isostructural and Isoelectronic Analogue of Phosphorene: Sonication-Assisted Synthesis, Chemical Stability, and Optical Properties, Y. Ye et al., Chem. Mater., 29, 8361−8368 (2017); DOI: 10.1021/acs.chemmater.7b02784.
• Anisotropic Spin Transport and Strong Visible-Light Absorbance in Few-Layer SnSe and GeSe, G. Shi et al., Nano Lett., 15, 6926−6931 (2015); DOI: 10.1021/acs.nanolett.5b02861.
• Band Structure and Photoelectric Characterization of GeSe Monolayers, Adv. Funct. Mater., 28, 1704855 (2018); DOI: 10.1002/adfm.201704855.
• Highly Anisotropic GeSe Nanosheets for Phototransistors with Ultrahigh Photoresponsivity, X. Zhou et al., Adv. Sci., 5, 1800478 (2018); DOI: 10.1002/advs.201800478.