Aluminium arsenide

Aluminium arsenide
Identifiers

CAS Number	22831-42-1^Y
3D model (Jmol)	Interactive image
ChemSpider	81112^Y
ECHA InfoCard	100.041.126
EC Number	245-555-0
PubChem CID	89859
InChI InChI=1S/Al.As^Y Key: MDPILPRLPQYEEN-UHFFFAOYSA-N^Y InChI=1/Al.As/rAlAs/c1-2 Key: MDPILPRLPQYEEN-LYSWLDLJAW
SMILES [Al]#[As]
Properties
Chemical formula	AlAs
Molar mass	101.9031 g/mol
Appearance	orange crystals
Density	3.72 g/cm³
Melting point	1,740 °C (3,160 °F; 2,010 K)
Solubility in water	reacts
Solubility	reacts in ethanol
Band gap	2.12 eV (indirect)
Electron mobility	200 cm²/(V·s) (300 K)
Thermal conductivity	0.9 W/(cm·K) (300 K)
Refractive index (n_D)	3 (infrared)
Structure
Crystal structure	Zinc Blende
Space group	T²_d-F-43m
Coordination geometry	Tetrahedral
Thermochemistry
Std molar entropy (S^o₂₉₈)	60.3 J/mol K
Std enthalpy of formation (Δ_fH^o₂₉₈)	-116.3 kJ/mol
Hazards
US health exposure limits (NIOSH):
PEL (Permissible)	[1910.1018] TWA 0.010 mg/m³
REL (Recommended)	Ca C 0.002 mg/m³ [15-minute]
IDLH (Immediate danger)	Ca [5 mg/m³ (as As)]
Related compounds
Related semiconductor materials	Aluminium gallium arsenide, Aluminium indium arsenide, Aluminium antimonide, Boron arsenide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y (what is ^YN ?)
Infobox references

Aluminium arsenide or aluminum arsenide (Al As) is a semiconductor material with almost the same lattice constant as gallium arsenide and aluminium gallium arsenide and wider band gap than gallium arsenide. (Al As) can form a superlattice with gallium arsenide (Ga As) which results in its semiconductor properties. Because (Ga As) and (Al As) have almost the same lattice constant, the layers have very little induced strain, which allows them to be grown almost arbitrarily thick. This allows for extremely high performance high electron mobility, HEMT transistors, and other quantum well devices.

It has the following properties:

Aluminum arsenide is a III-V compound semiconductor material and is an advantageous material for the manufacture of optoelectronic devices, such as light emitting diodes.

Aluminum arsenide can be prepared using well-known methods, such as liquid and vapor-phase epitaxy techniques or melt-growth techniques. However, aluminum arsenide crystals prepared by these methods are generally unstable and generate arsine (As H₃) when exposed to moist air.

Little work has been reported on the preparation of aluminum arsenide, mainly because of the practical difficulties involved. Preparation from the melt is difficult because of the high melting point of the compound (about 1,700 °C) and of the extreme reactivity of aluminum at this temperature. A few workers have prepared small crystals from the melt, and polycrystalline ingots have also been produced. The best of this material has an impurity carrier density of the order of 10¹⁹/cm³ and is p-type.

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