Indium Phosphide (InP) Semiconductors

Topics Covered

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


Indium phosphide (InP) includes phosphorus and indium and is a binary semiconductor. It has a zincblende crystal structure similar to GaAs and almost all the III-V semiconductors.


Indium phosphide finds applications in the following:

  • It has superior electron velocity due to which it is used in high-frequency and high-power electronics.
  • It has a direct bandgap unlike many semiconductors hence is used for optoelectronics devices like laser diodes.
  • Indium phosphide is also used as a substrate for optoelectronic devices based on epitaxial indium gallium arsenide.

Chemical Properties

The chemical properties of indium phosphide are provided in the table below:

Chemical Properties
Chemical Formula InP
Molecular Weight 145.792 g/mol
CAS No. 22398-80-7
IUPAC Name Indium phosphide
Group III-V
Band Gap 1.344 eV
Band Gap Type Direct
Crystal Structure Zinc Blende
Symmetry Group Td2-F43m
Lattice Constant 5.8687 Angstroms

Electrical Properties

The electrical properties of indium phosphide are provided in the table below:

Electrical Properties
Intrinsic Carrier Concentration 2x1016cm-3
Electron Mobility ≤ 400cm2 V-1 s-1
Hole Mobility ≤ 200 cm2 V-1 s-1
Electron Diffusion Coefficient ≤ 130 cm2 s-1
Hole Diffusion Coefficient ≤ 5 cm2 s-1
Electrical resistivity 8.6x107Ωcm

Thermal, Mechanical and Optical Properties

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

Mechanical Properties
Melting Point 1062 °C
Density 4.81 g cm-3
Bulk Modulus 7.1x1011 dyn cm-2
Thermal Properties
Thermal Conductivity 0.68 W cm-1 °C-1
Thermal Diffusivity 0.372 cm2 s-1
Thermal Expansion Coefficient 4.60x10-6 °C-1
Optical Properties
Refractive Index (589 nm @ 293 K) 3.1
Radiative Recombination Coefficient (@ 300 K) 1.2x10-10 cm3 s-1

Safety Information

HMIS Hazard Rating:

  • Health: 3 – Major injury likely unless medical action taken and prompt treatment given
  • Flammability: 2 –Must be moderately heated or exposed to high
  • ambient temperature before ignition takes place
  • Reactivity: 2 - May undergo violent chemicalchanges at normal temperature and pressure with low risk for explosion
  • May react violently with water or form peroxides upon exposure to air.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback