Cadmium Telluride

Cadmium Telluride particles are tiny particles composed of cadmium (Cd) and tellurium (Te), which are widely used in semiconductors, solar cells, etc. They have unique photovoltaic properties, and factors such as the particle size and purity will have a key impact on the effectiveness of their application.

Characteristics

Chemical formula: CdTe

Molecular weight: 240.01 g/mol

CAS No.: 1306-25-8

Solubility: In terms of solubility in water, CdTe has a very low solubility and is insoluble in water, but will be corroded by many acids such as hydrobromic acid and hydrochloric acid.

Density: approximately 5.85-6.2 g/cm³, density data may vary slightly depending on the morphology of the particles, purity, and method of measurement.

Colour: usually grey to dark grey.

Melting point: 1041°C-1092°C

Boiling point: around 1130°C

Refractive index: 2.67.

Lattice structure: cubic crystal structure, lattice constant is 6.482 Å.

Dielectric constant: 10.2

Band gap: 1.44 eV, which makes CdTe important for photovoltaic applications such as solar cells, with a moderate band gap width for better absorption of solar energy.

Hole mobility: 65 cm²/Vs

Electron mobility: 700 cm²/Vs

Coefficient of thermal expansion: 5.9×10-⁶/K

Specific heat capacity: 0.21 J/gK

Thermal conductivity: 0.06 W/cmK

Young’s modulus: 3.7×10¹¹¹ dyne /cm²

Modulus of rupture: 2.2×10⁸ dyne /cm²

Poisson’s ratio: 0.41

Applications

Solar cell field:

Thin-film solar cells: Cadmium Telluride thin-film solar cells are one of their most important applications. Cadmium Telluride has a suitable forbidden band width (1.44-1.5 eV) for better absorption of solar energy and a high light absorption coefficient, with optical absorption exceeding 90% under standard AM1.5 conditions for a film of only 2 μm thickness. The production cost of this cell is relatively low and the production process is relatively simple, so it has a certain degree of competitiveness in the solar cell market.

Semiconductor field:

Semiconductor materials: As an important II-VI compound semiconductor material, Cadmium Telluride is used in the preparation of semiconductor devices such as transistors and diodes. Its crystal structure is sphalerite type, with direct leaping energy band structure and high room temperature electron mobility, which is suitable for some electronic devices with specific requirements on semiconductor performance.

Doped semiconductors: Cadmium Telluride can be doped with different impurities to make it an n-type or p-type semiconductor material, thus meeting the needs of different semiconductor devices. For example, replacing Cd with In forms an n-type semiconductor, while replacing Cd with Cu, Ag, or Au forms a p-type semiconductor.

Detectors:

Infrared detectors: Cadmium Telluride responds better to infrared radiation and can be used to make infrared detectors, which have important applications in military, security, aerospace and other fields. For example, it can be used to detect the infrared radiation of target objects to achieve the detection, tracking and identification of targets.

X-ray detectors: Specially treated Cadmium Telluride can be used as an X-ray detector for medical imaging, materials testing, industrial flaw detection and other applications. It is capable of converting X-rays into electrical or other detectable signals to enable the detection and analysis of X-rays.

Gamma ray detectors: Due to its high atomic number and density, Cadmium Telluride has good blocking and absorbing ability for gamma rays, so it can be used to make gamma ray detectors, which are used in the fields of nuclear radiation monitoring and detection of radioactive substances.

Optical field:

Infrared optical windows and lenses: Cadmium Telluride has good transmittance in the infrared wavelength band, and can be used to make infrared optical windows and lenses, which are used in infrared thermal imagers, infrared telescopes and other optical instruments to allow infrared light to pass through, and realise infrared observation of the target.

Electro-optical modulator: Cadmium Telluride has a large electro-optical coefficient, which can be used to make electro-optical modulator to change its optical properties by applying an electric field to realise the modulation of optical signals, such as the modulation of the intensity, phase and frequency of the light, which has the prospect of being applied in the fields of optical communication and optical information processing.

Other fields:

Phosphor material: in some special light-emitting devices, Cadmium Telluride can be used as a phosphor material to emit light of specific wavelengths by absorbing energy, which is used to make light-emitting diodes (LEDs), phosphors and so on.

Laboratory research: Because of its unique physical and chemical properties, Cadmium Telluride is often used as a research object in laboratory research in the fields of materials science, chemistry, physics, etc. for exploring the scientific problems of semiconductor materials in terms of their properties, optoelectronic characteristics, crystal structures, etc.