Indium phosphide

"InP" redirects here. For other uses, see INP.

Indium phosphide (InP) is a binary semiconductor composed of indium and phosphorus. It has a face-centered cubic ("zincblende") crystal structure, identical to that of GaAs and most of the III-V semiconductors.

Indium phosphide

Names
Other names Indium(III) phosphide
Identifiers
CAS Number	22398-80-7 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	28914 Y
ECHA InfoCard	100.040.856
PubChem CID	31170
UNII	SD36LG60G1 Y
CompTox Dashboard (EPA)	DTXSID3031444
InChI InChI=1S/In.P Y Key: GPXJNWSHGFTCBW-UHFFFAOYSA-N Y InChI=1/In.P/rInP/c1-2 Key: GPXJNWSHGFTCBW-HIYQQWJCAF
SMILES [In+3].[P-3] [In]#P
Properties
Chemical formula	InP
Molar mass	145.792 g/mol
Appearance	black cubic crystals[1]
Density	4.81 g/cm3, solid[1]
Melting point	1,062 °C (1,944 °F; 1,335 K)[1]
Solubility	slightly soluble in acids
Band gap	1.344 eV (300 K; direct)
Electron mobility	5400 cm2/(V·s) (300 K)
Thermal conductivity	0.68 W/(cm·K) (300 K)
Refractive index (nD)	3.1 (infrared); 3.55 (632.8 nm)[2]
Structure
Crystal structure	Zinc blende
Lattice constant	a = 5.8687 Å [3]
Coordination geometry	Tetrahedral
Thermochemistry[4]
Heat capacity (C)	45.4 J/(mol·K)
Std molar entropy (S⦵298)	59.8 J/(mol·K)
Std enthalpy of formation (ΔfH⦵298)	−88.7 kJ/mol
Gibbs free energy (ΔfG⦵)	−77.0 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Toxic, hydrolysis to phosphine
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Indium nitride Indium arsenide Indium antimonide
Other cations	Aluminium phosphide Gallium phosphide
Related compounds	Indium gallium phosphide Aluminium gallium indium phosphide Gallium indium arsenide antimonide phosphide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Manufacturing

Indium phosphide nanocrystalline surface obtained by electrochemical etching and viewed under scanning electron microscope. Artificially colored in image post-processing.

Indium phosphide can be prepared from the reaction of white phosphorus and indium iodide at 400 °C.,^[5] also by direct combination of the purified elements at high temperature and pressure, or by thermal decomposition of a mixture of a trialkyl indium compound and phosphine.^[6]

Applications

The application fields of InP splits up into three main areas. It is used as the basis for optoelectronic components,^[7] high-speed electronics,^[8] and photovoltaics^[9]

High-speed optoelectronics

InP is used as a substrate for epitaxial optoelectronic devices based other semiconductors, such as indium gallium arsenide. The devices include pseudomorphic heterojunction bipolar transistors that could operate at 604 GHz.^[10]

InP itself has a direct bandgap, making it useful for optoelectronics devices like laser diodes and photonic integrated circuits for the optical telecommunications industry, to enable wavelength-division multiplexing applications.^[11] It is used in high-power and high-frequency electronics because of its superior electron velocity with respect to the more common semiconductors silicon and gallium arsenide.

Optical Communications

InP is used in lasers, sensitive photodetectors and modulators in the wavelength window typically used for telecommunications, i.e., 1550 nm wavelengths, as it is a direct bandgap III-V compound semiconductor material. The wavelength between about 1510 nm and 1600 nm has the lowest attenuation available on optical fibre (about 0.2 dB/km).^[12] Further, O-band and C-band wavelengths supported by InP facilitate single-mode operation, reducing effects of intermodal dispersion.

Photovoltaics and optical sensing

InP can be used in photonic integrated circuits that can generate, amplify, control and detect laser light.^[13]

Optical sensing applications of InP include

• Air pollution control by real-time detection of gases (CO, CO₂, NO_X [or NO + NO₂], etc.).
• Quick verification of traces of toxic substances in gases and liquids, including tap water, or surface contaminations.
• Spectroscopy for non-destructive control of product, such as food. Researchers of Eindhoven University of Technology and MantiSpectra have already demonstrated the application of an integrated near-infrared spectral sensor for milk.^[14] In addition, it has been proven that this technology can also be applied to plastics and illicit drugs.^[15]