Gallium Nitride

Title: Gallium Nitride
CAS Registry Number: 25617-97-4
Additional Names: Gallium mononitride
Molecular Formula: GaN
Molecular Weight: 83.73
Percent Composition: Ga 83.27%, N 16.73%
Literature References: Semiconductor material. Prepn: W. C. Johnson et al., J. Phys. Chem. 36, 2651 (1932); and wurtzite structure determn: R. Juza, H. Hahn, Z. Anorg. Allg. Chem. 239, 282 (1938). Prepn of single crystalline GaN by vapor deposition: H. P. Maruska, J. J. Tietjen, Appl. Phys. Lett. 15, 327 (1969). Luminescence studies: H. G. Grimmeiss, H. Koelmans, Z. Naturforsch. 14a, 264 (1959). P-type doping: H. Amano et al., Jpn. J. Appl. Phys. 28, L2112 (1989). Fabrication of blue light emitting diodes (LEDs): S. Nakamura et al., ibid. 30, L1998 (1991). Potential use of GaN LEDs in phototherapy for jaundice: D. S. Seidman et al., J. Pediatr. 136, 771 (2000). Review of properties and crystal growth techniques: S. Strite, H. Morkoç, J. Vac. Sci. Technol. B 10, 1237-1266 (1992); and applications: S. Keller, S. P. Denbaars, Curr. Opin. Solid State Mater. Sci. 3, 45-50 (1997); S. J. Pearton et al., Materials Today 5, 24-31 (June, 2002); of thin film growth techniques and optical properties: R. F. Davis et al., Proc. IEEE 90, 993-1004 (2002).
Properties: Equilibrium crystal structure is hexagonal wurtzite; lattice constants at 300 K: a = 3.189 Å; c = 5.185 Å. Less thermodynamically stable cubic zinc blende structures can be grown on cubic substrates; lattice constant a = 4.503 Å. mp 2500° (2800 K). Thermal conductivity: 1.3 W/cm K. Bandgap at 300 K: 3.39 eV. n (1 eV) = 2.33. n (3.38 eV) = 2.67. Exceedingly chemically and thermally stable. Insol in H2O, acids, and bases at room temp. Dissolves slowly in hot alkalis.
Melting point: Equilibrium crystal structure is hexagonal wurtzite; lattice constants at 300 K: a = 3.189 Å; c = 5.185 Å. Less thermodynamically stable cubic zinc blende structures can be grown on cubic substrates; lattice constant a = 4.503 Å. mp 2500° (2800 K)
Index of refraction: n (1 eV) = 2.33; n (3.38 eV) = 2.67
Use: Blue and UV light emitter with applications in semiconductor devices including: LEDs, laser diodes, lighting, displays, and data storage.
Gallium Oxide Gallium Phosphide Gallium Trifluoride Gallocyanine Gallopamil

Gallium nitride
GaNcrystal.jpg
Wurtzite polyhedra.png
Identifiers
CAS number 25617-97-4 YesY
PubChem 117559
ChemSpider 105057 YesY
RTECS number LW9640000
Jmol-3D images Image 1
Properties
Molecular formula GaN
Molar mass 83.73 g/mol
Appearance yellow powder
Density 6.15 g/cm3
Melting point >2500 °C[2]
Solubility in water Reacts.
Band gap 3.4 eV (300 K, direct)
Electron mobility 440 cm2/(V·s) (300 K)
Thermal conductivity 2.3 W/(cm·K) (300 K) [1]
Refractive index (nD) 2.429
Structure
Crystal structure Wurtzite
Space group C6v4-P63mc
Lattice constant a = 3.186 Å, c = 5.186 Å [3]
Coordination
geometry
Tetrahedral
Hazards
EU Index Not listed
Flash point Non-flammable
Related compounds
Other anions Gallium phosphide
Gallium arsenide
Gallium antimonide
Other cations Boron nitride
Aluminium nitride
Indium nitride
Related compounds Aluminium gallium arsenide
Indium gallium arsenide
Gallium arsenide phosphide
Aluminium gallium nitride
Indium gallium nitride
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor commonly used in bright light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic,[4][5] high-power and high-frequency devices. For example, GaN is the substrate which makes violet (405 nm) laser diodes possible, without use of nonlinear optical frequency-doubling.

Its sensitivity to ionizing radiation is low (like other group III nitrides), making it a suitable material for solar cell arrays for satellites. Military and space applications could also benefit as devices have shown stability in radiation environments.[6] Because GaN transistors can operate at much higher temperatures and work at much higher voltages than gallium arsenide (GaAs) transistors, they make ideal power amplifiers at microwave frequencies.