High-Purity Germanium

When Dmitri Mendeleev first sketched his periodic table in 1871, he left a deliberate gap beneath silicon, assigning it the provisional name "eka-silicon" and predicting its atomic weight, density, and chemical properties with uncanny precision. Fifteen years later, German chemist Clemens Winkler isolated this very element from the mineral argyrodite and named it germanium — the most celebrated vindication of Mendeleev's periodic law. Today, this lustrous gray-white metalloid — atomic number 32, diamond cubic crystal structure, a narrow bandgap of 0.67 eV — ranks among the most strategically critical materials on Earth, indispensable to thermal imaging systems, space-bound solar arrays, and the fiber optic networks that carry the world's data.

Eata Energy supplies high-purity germanium metal across grades from 4N (99.99%) to 6N (99.9999%), available as single-crystal and polycrystalline ingots, wafers, sputtering targets, powder, and precision optical blanks. Each batch undergoes rigorous characterization via GDMS and ICP-MS, with comprehensive analytical documentation provided to support your infrared optical, photovoltaic, semiconductor, or detector fabrication program.

Fundamental Properties of Germanium

Germanium's diamond cubic crystal structure — shared with silicon and diamond — endows it with a unique combination of semiconductor properties, high refractive index, and broad infrared transparency that no other element can replicate in a single material form.

Figure 1: Zone-refined high-purity germanium crystal bar with characteristic dark silver-gray metallic luster

Germanium naturally occurs in five stable isotopes, with ⁷²Ge constituting approximately 27.7% of natural abundance. This isotope has attracted intense scientific interest as the target material in neutrinoless double-beta decay experiments, which seek to determine whether the neutrino is its own antiparticle — a discovery that would fundamentally reshape the Standard Model of particle physics.

Available Forms & Specifications

Our germanium product range addresses the specific requirements of infrared optics, semiconductor epitaxy, radiation detection, and advanced research, with each form manufactured and packaged to preserve surface quality and crystallographic integrity.

Germanium Ingot & Crystal Bar

Single-crystal and polycrystalline germanium ingots serve as feedstock for wafer slicing, optical blank fabrication, and crystal growth research. Material is produced via Czochralski or zone-refining methods depending on the target application and purity requirement.

• Crystal orientation: <111>, <100>, or custom (single-crystal)
• Diameter: up to 150 mm single-crystal, up to 450 mm polycrystalline
• Purity: 4N (99.99%) to 6N (99.9999%)
• Resistivity: 0.03–500 Ω·cm, N-type (Sb-doped) or P-type (B-doped)

Germanium Wafers & Optical Blanks

Polished germanium wafers serve as substrates for III-V multijunction solar cell epitaxy, while optical blanks are fabricated into lenses, windows, prisms, and ATR crystals for infrared spectroscopy and thermal imaging systems.

• Wafer diameter: 50.8 mm (2″) to 150 mm (6″)
• Optical blank diameter: up to 335 mm (single-crystal), up to 450 mm (polycrystalline)
• Thickness: 0.5 mm to 25.4 mm, custom specifications available
• Surface finish: fine ground, polished, or AR-coated (DLC, ZnS)

Figure 2: Polished germanium wafer with mirror-like surface and crystallographic orientation flats

Germanium Sputtering Targets & Evaporation Material

HIP-consolidated germanium sputtering targets and zone-refined evaporation pellets support research into Ge-channel CMOS transistors, SiGe heterojunction bipolar transistors, and novel infrared thin-film coatings.

• Target purity: 99.99% (4N) to 99.9999% (6N)
• Dimensions: 2-inch to 8-inch diameter, planar configuration
• Evaporation pellets: 3×3 mm to 6×6 mm cylinders

Germanium Powder

High-purity germanium powder serves as feedstock for alloy development, thermoelectric material synthesis, and research into germanium-based nanostructures including germanene — the two-dimensional topological insulator analog to graphene.

• Particle size: 1 μm to 150 μm, nano (50–100 nm) available
• Purity: 99.99% (4N) to 99.9999% (6N)
• Morphology: irregular (crushed) or spherical (atomized)

Key Application Areas

Infrared Optics for Thermal Imaging

Germanium's defining optical property is its broad infrared transparency — transmitting wavelengths from 2 to 14 μm, encompassing both the mid-wave IR (MWIR, 3–5 μm) and long-wave IR (LWIR, 8–12 μm) atmospheric windows. With a refractive index of approximately 4.0 at 10 μm — the highest of any common IR optical material — germanium lenses achieve high numerical apertures in remarkably compact form factors, enabling miniaturized LWIR camera modules for automotive night vision, aerial thermography, firefighting thermal imagers, and military targeting systems. The strong Fresnel reflection losses at uncoated surfaces (~36% per surface) are mitigated by standard diamond-like carbon (DLC) and zinc sulfide anti-reflection coatings, achieving >95% transmission per surface in operational systems.

Figure 3: Precision-polished germanium plano-convex lens mounted on an optical test platform

Multijunction Space Solar Cells

Germanium substrates dominate the multijunction solar cell market for space applications, where efficiency takes precedence over cost. Single-crystal germanium wafers serve as the mechanical substrate and bottom-cell active layer for triple-junction GaInP₂/GaAs/Ge cells that have achieved efficiencies exceeding 47% under concentrated sunlight. The lattice constant of germanium (5.658 Å) provides excellent matching for III-V epitaxial growth, while its mechanical robustness withstands the extreme thermal cycling of orbital environments. Over 25 million 5G base stations expected by 2028 will drive demand for InP substrates grown from high-purity indium, while the concurrent expansion of low-earth-orbit satellite constellations continues to fuel germanium consumption for space photovoltaic systems.

High-Purity Germanium Radiation Detectors

Ultra-high-purity germanium (HPGe), achieved through multiple zone-refining passes, reaches net impurity concentrations below 10¹⁰ cm⁻³ — equivalent to one impurity atom per 10¹³ germanium atoms. When cooled to liquid nitrogen temperature (77 K), HPGe crystals function as the premier gamma-ray detectors in nuclear medicine, astrophysics, and homeland security applications. The superior energy resolution of HPGe detectors — typically 0.1–0.2% FWHM at 1.33 MeV — far exceeds that of scintillation-based alternatives, enabling precise isotope identification in complex gamma-ray spectra.

Figure 4: Multijunction solar cell on germanium substrate with gold wire bonds on test fixture

Fiber Optic Core Doping

In the form of germanium tetrachloride (GeCl₄), germanium serves as the key dopant in silica optical fiber, raising the refractive index of the fiber core above the cladding to achieve total internal reflection. Essentially all single-mode fiber worldwide contains a germanium-doped silica core. The global rollout of 5G infrastructure, data center expansion, and fiber-to-the-home deployment continues to drive substantial germanium consumption in telecommunications — approximately 30% of global refinery output.

SiGe Microelectronics & Beyond

Silicon-germanium (SiGe) alloys have re-emerged as critical materials in high-frequency microelectronics, leveraging germanium's higher electron and hole mobilities compared with silicon to achieve cutoff frequencies above 500 GHz in heterojunction bipolar transistors. SiGe BiCMOS technology powers millimeter-wave radar, 5G/6G transceivers, and optical communication ICs. At the research frontier, epitaxial germanium channels are being integrated into CMOS architectures to extend Moore's Law, while monolayer germanene — the germanium analog of graphene — exhibits promise as a two-dimensional topological insulator for quantum computing applications.

Figure 5: Illuminated fiber optic bundle with glowing tips transmitting data signals

Purity Grades & Recommended Applications

Germanium purity selection directly influences device performance, detector energy resolution, and optical transmission characteristics. The matrix below provides practical guidance for grade selection.

Analytical Verification & Documentation

Eata Energy applies a rigorous multi-technique analytical protocol to certify every germanium batch, with results compiled in a Certificate of Analysis delivered with each shipment.

• GDMS: bulk trace element quantification at ppb levels for 5N–6N grades
• ICP-MS: multi-element impurity profiling at sub-ppb detection limits
• Hall effect measurement: carrier concentration, mobility, and resistivity
• FTIR transmission spectroscopy: optical absorption coefficient verification
• X-ray diffraction: crystal orientation and lattice parameter confirmation
• XRF: rapid non-destructive bulk composition screening

Tailored Specifications & Custom Solutions

Frontier research in infrared optics, quantum devices, and next-generation photovoltaics frequently demands germanium configurations beyond standard catalog offerings. Eata Energy's technical team collaborates directly with your engineers to develop bespoke solutions.

• Custom crystal growth: specific orientations, doping profiles, and resistivity targets
• Precision optical fabrication: aspheric lenses, freeform surfaces, diffractive optical elements
• Enhanced purity: 6N+ HPGe material with dedicated zone refining and cryogenic detector verification
• AR coating services: DLC, ZnS, and multilayer coatings optimized for specific IR bands
• Flexible scale: from single wafers and optical blanks to production-scale ingot quantities

Engage our materials scientists during your project scoping phase to optimize germanium grade, crystal orientation, and surface specification for your specific optical system, detector architecture, or epitaxial growth protocol.

For Research or Industrial Raw Materials, Not For Personal Medical Use!