Selenium (Se) Semiconductors

Topics Covered

Chemical Properties
Electrical Properties
Thermal, Mechanical and Optical Properties
Safety Information


Selenium is a member of the sulfur group of nonmetallic elements. It exists in several allotropic forms: the most common forms are a red crystalline material/powder and a gray crystalline metal-like form known as metallic selenium.

It exhibits photovoltaic and photoconductive activity. It was discovered by Jöns Jakob Berzelius in 1817. Selenium was named after the Greek word "Selene", which means moon.


Selenium finds applications in the following:

  • Solar cells and photoconductor applications
  • Manganese electrolysis
  • Alloys and glass production
  • Modification of vulcanization catalysts used in rubber production
  • DC power surge protection
  • Fabrication of quantum dots
  • Toning of photographic prints
  • X-ray crystallography.

Chemical Properties

The chemical properties of selenium are provided in the table below:

Chemical Properties
Chemical Formula Se
Molecular Weight 78.96
CAS No. 7782-49-2
Group 16
Crystal Structure Hexagonal
Lattice Constant 4.360 Å

Electrical Properties

The electrical properties of selenium are provided in the table below:

Electrical Properties
Critical Superconducting Temperature 6.75-6.95 K
Dielectric Constant 6.6
Band Gap 1.5 eV
Hole Mobility 5 cm2/Vs

Thermal, Mechanical and Optical Properties

The thermal, mechanical and optical properties of selenium are provided in the tables below:

Thermal Properties
Heat of Fusion 84 J/g
Heat of Vaporization 3140 J/g
Thermal Expansion Coefficient 37µm/m°C
Specific Heat Capacity 0.2926 J/g°C
Thermal Conductivity 1.31 W/mK
Melting Point 220°C
Mechanical Properties
Modulus of Elasticity 57.9 GPa
Shear Modulus 6.46 GPa
Optical Properties
Refractive Index 2.5

Safety Information

Safety Information
GHS Hazard Statements H331 - Toxic if inhaled.
H301 - Toxic if swallowed
H373 - May cause damage to organs through prolonged or repeated exposure
H413 - May cause long lasting harmful effects to aquatic life
Safety Precautions P261- Avoid breathing dust, gas, fume, vapors, spray, mist.
P264 - Wash exposed skin thoroughly after handling.
P270 - Do no eat, drink or smoke when using this product.
P273 - Avoid release to the environment.

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