Polycrystalline germanium ingot
Properties
Chemical symbol: Ge
Name: Polycrystalline germanium / germanium ingots
CAS No.: 7440-56-4
Molar mass: 72.63 g/mol
Density: 5.32 g/cm³
Melting point: approx. 938 °C
Boiling point: approx. 2833 °C
Purity: typically 99.999-99.999999% (5N-8N)
Band gap: approx. 0.66 eV at room temperature
Color: gray with metallic luster
Form: zone-refined ingots, round ingots or cast blocks
Polycrystalline germanium ingots are a primary high-purity product form of the semiconductor element germanium. The material has a gray metallic appearance, is relatively brittle and is commonly supplied as trapezoidal zone-refined ingots, round ingots or cast blocks.
Polycrystalline germanium is characterized by exceptionally high chemical purity. Grades ranging from 99.999% (5N) to 99.999999% (8N) are typical for demanding high-technology applications. Such low impurity levels are especially important for semiconductors, infrared optics and sensitive detector systems.
At room temperature, germanium has an indirect band gap of approximately 0.66 eV. One of its most important properties is excellent infrared transparency, particularly across the wavelength range of roughly 2 to 14 µm. This makes germanium metal highly suitable for lenses, windows and prisms used in thermal imaging and other infrared optical systems.
Unlike many metals, germanium expands slightly as it solidifies from the melt. It is stable in air at room temperature and forms a passivating germanium dioxide layer, GeO₂, at elevated temperatures. The material is insoluble in water and dilute acids but dissolves in oxidizing acid mixtures.
High-purity germanium is mainly produced by reducing purified germanium dioxide with hydrogen, followed by electrothermal zone refining. The zone-refining process significantly reduces foreign-atom concentrations and produces material suitable for demanding electronic, optical and detector applications.
Germanium metal is particularly important in infrared optics, thermal imaging, semiconductor technology, fiber optics and radiation detection. Polycrystalline germanium ingots also serve as a homogeneous feedstock for growing single-crystal germanium by the Czochralski process.
Would you like to buy germanium? Auremo can provide information about available purity grades, ingot forms and delivery conditions. The germanium price, germanium metal price and germanium price per kg depend on purity, dimensions, product form, quantity and supply conditions.
Advantages
• Extremely high purity up to 8N depending on grade
• Very low impurity concentrations after zone refining
• Excellent transmission in the mid- and long-wave infrared ranges
• Suitable for high-performance thermal imaging optics
• Excellent feedstock for single-crystal growth
• Favorable semiconductor properties
• High charge-carrier mobility
• Suitable for highly sensitive detector systems
Applications
• Infrared optics
• Thermal imaging cameras and night-vision systems
• IR lenses, windows and prisms
• Semiconductor technology
• Czochralski growth of single-crystal germanium
• Germanium wafers and semiconductor substrates
• Space photovoltaic applications
• Fiber-optic and light-waveguide industry
• Production of germanium tetrachloride GeCl₄
• Doping of silica fiber cores
• High-purity germanium detectors (HPGe)
• High-resolution gamma spectroscopy
Auremo offers high-purity polycrystalline germanium and other specialty materials for industrial and advanced technical applications. If you have any questions about purity, ingot form, available dimensions or delivery conditions, please contact us directly.
