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Gallium Nitride

GaN inorganic
Molar Mass
83.730 g/mol
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Properties

StateSolid (crystalline)
ColorTransparent to pale yellow
SolubilityInsoluble in water, acids, and bases below 800 °C; slowly dissolves in hot concentrated alkali
Melting Point2500 °C (decomposes under atmospheric N2 above 1000 °C)

About Gallium Nitride

Gallium nitride (GaN, 83.73 g/mol) is the III-V wide-bandgap semiconductor that finally cracked the blue-LED problem after thirty years of failure. Stable form is hexagonal wurtzite — Ga and N atoms in alternating (0001) planes — with a direct bandgap of 3.4 eV that puts its band-edge emission at 365 nm in the UV, tunable into the visible by alloying with InN to form InGaN. The wurtzite structure is non-centrosymmetric and strongly polar along the c-axis, which gives GaN a piezoelectric and spontaneous polarization that can be either useful (the 2DEG sheet at AlGaN/GaN heterointerfaces, basis of every GaN HEMT) or a nuisance (quantum-confined Stark effect in light emitters, the QCSE that limits InGaN-LED efficiency at high In content). The blue LED itself is the central story. Before 1993, every GaP and GaAs device topped out in the green; ZnSe-based blue emitters degraded in days from defect-driven dark-line growth. Shuji Nakamura at Nichia Corporation solved both problems simultaneously: a low-temperature GaN buffer layer on sapphire that absorbed the 16% lattice mismatch, an Mg-doped GaN that finally went p-type after thermal annealing dissociated the Mg-H complex (Hiroshi Amano and Isamu Akasaki had identified the H-passivation problem at Nagoya), and an InGaN/GaN multiple-quantum-well active region. Combined with a YAG:Ce phosphor on top, the blue LED became the white LED, and Nakamura, Akasaki, and Amano shared the 2014 Nobel Prize in Physics. GaN is now the dominant blue-violet laser-diode material (Blu-ray pickups), the breakthrough wide-bandgap power transistor (every 65 W gallium-nitride USB-C charger, growing share of EV inverters and 5G base stations), and the workhorse of solid-state lighting.

Where you'll encounter it

If you are reading this on a phone that charges over USB-C with one of those palm-sized 65 W or 100 W bricks, the brick is built around GaN HEMTs from Navitas, GaN Systems, or EPC — the only way to fit that much power in that volume is to switch at 500 kHz to 1 MHz, which silicon MOSFETs cannot do efficiently. In a Blu-ray player the violet pickup laser (405 nm) is a GaN laser diode; in a server farm the high-density power supplies feeding NVIDIA H100 GPUs use GaN-on-Si stages because they save 30% volume and 5% efficiency over silicon SiC alternatives.

Common Uses

  • InGaN/GaN multi-quantum-well blue LEDs combined with YAG:Ce for white-LED lighting
  • 405 nm Blu-ray and laser-projector violet diode lasers
  • AlGaN/GaN HEMT power transistors in 65-200 W USB-C fast chargers
  • GaN-on-Si half-bridges in datacom and AI-server high-density power supplies
  • S-band and X-band RF power amplifiers in 5G base stations and naval radar
  • 270 nm AlGaN deep-UV LEDs for water and surface disinfection
  • Schottky diodes for 600-1200 V solar microinverter and EV onboard chargers
  • UV-C and solar-blind photodetectors for flame and corona discharge sensing

Safety Information

GHS: Eye irritation (Cat 2A, H319), Specific target organ toxicity single exposure (Cat 3, respiratory irritation, H335). Bulk crystal and epitaxial film are biologically inert and non-toxic — most consumer products embedding GaN (LEDs, chargers) require no special handling. Dust from wafer dicing or grinding falls under the OSHA 15 mg/m3 total-dust nuisance limit; gallium-specific TLVs do not exist. GaN MOCVD process gases (trimethylgallium, ammonia, silane) carry their own severe hazards but the deposited solid does not. End-of-life recycling extracts gallium from scrapped LEDs and chargers via acid leach. Fire-resistant — does not burn or decompose below ~1000 °C, well above any normal product environment.

This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.

Constituent Elements

Ga — Gallium N — Nitrogen

Frequently Asked Questions

What is the molar mass of gallium nitride?
GaN has a molar mass of 83.73 g/mol — Ga (69.723) + N (14.007). Density is 6.15 g/cm³, surprisingly high for a binary nitride and a function of the dense wurtzite packing. The molar mass matters when you are growing thick HVPE GaN buffer layers and need to calculate gas flows: for a 1 µm layer over a 6-inch wafer, you are depositing roughly 1.1 g of GaN, which sets the minimum trimethylgallium and NH3 throughput your reactor needs to sustain growth rate.
Why was the blue LED so hard to invent?
Three problems compounded each other. Blue light requires bandgaps above 2.6 eV — GaAs (1.43 eV) and GaP (2.3 eV) cannot reach it. GaN had the right bandgap (3.4 eV) but had a 16% lattice mismatch with sapphire (the only practical substrate), which made the early GaN films a defect-ridden mess that would not lase. Worse, GaN doped with Mg refused to go p-type because Mg-H complexes formed during growth and passivated the acceptors — nobody understood this until Hiroshi Amano accidentally fixed it with low-energy electron-beam irradiation in 1989, and Shuji Nakamura formalized the thermal-anneal version in 1992. Nakamura's 1993 paper combining a low-temperature GaN buffer on sapphire, p-type Mg:GaN, and an InGaN/GaN MQW was the breakthrough that earned the 2014 Nobel Prize for Akasaki, Amano, and Nakamura.
Why are GaN transistors replacing silicon?
Three properties combine. Wide bandgap (3.4 eV) gives a high breakdown field (~3 MV/cm vs silicon's 0.3), so GaN devices can block the same voltage in a layer ten times thinner. The 2DEG at the AlGaN/GaN heterointerface, induced entirely by polarization without intentional doping, has a sheet density above 10^13/cm² and electron mobility around 2000 cm²/V·s. And GaN-on-silicon epitaxy means GaN HEMT die cost is approaching mainstream silicon levels. The combination lets a GaN HEMT switch in nanoseconds at hundreds of volts with low on-resistance — exactly what fast chargers, server PSUs, EV inverters, and 5G PAs need. Silicon MOSFETs hit a wall around 200 V and 100 kHz; GaN clears it cleanly.