Aluminium gallium nitride AlGaN
AlxGa1-xN, an alloy of aluminium nitride (AlN) and gallium nitride (GaN)
Aluminium gallium nitride (AlGaN) is an alloy of aluminium nitride and gallium nitride, written AlxGa1-xN.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Bandgap tuning
3.4 to 6.2 eV
Solar-blind cut-off
280 nm
Solar rejection
1000x
Quantum efficiency
48%
Recipe, share of the weight
- Al not statedAluminium
- Ga not statedGallium
- N not statedNitrogen
Best for
Ultraviolet detectors that must ignore sunlight, such as solar-blind work below 280 nm (BAE Systems) and planetary UV instruments (NASA Goddard)
Weakest at
Few material constants for the alloy were found. The numbers here are mostly device results, and the cut-off figures differ between sources (see gaps)
Risk at a glance
- People No data. No hazard data recorded
- If it fails No data. No failure risks recorded
- Corrosion No data. No corrosion data recorded
Quick facts: AlGaN
| Property | Value | Basis |
|---|---|---|
| Thermal conductivity | 165 to 187 W/(m·K) | 3 sourced values across conditions |
What is the thermal conductivity of Aluminium gallium nitride (AlGaN)?
Aluminium gallium nitride (AlGaN) has a thermal conductivity of 165 to 187 W/(m·K). The range covers 3 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is Aluminium gallium nitride (AlGaN) used for?
Uses recorded in the sources include Back-illuminated solar-blind UV focal-plane array (256 x 256 pixels); UV detector for planetary missions; UV sensing instruments for plume, flame, lidar and bio-agent work.
Why it exists
Aluminium gallium nitride (AlGaN) is a semiconductor that can be tuned across the ultraviolet. NASA gives direct bandgaps of 3.4 eV for GaN and 6.2 eV for AlN, and the aluminium fraction sets the value in between. A detector that absorbs only below a chosen wavelength can ignore the visible and near-visible light of the Sun. NASA Goddard works on this family of detectors for next-generation ultraviolet planetary missions.
Where it's used
Solar-blind ultraviolet focal-plane arrays
A 2006 article describes BAE Systems' 256 x 256 back-illuminated AlGaN hybrid arrays, with an absorber that cuts off at 280 nm and a photosensitivity band of 260 to 280 nm.
Planetary ultraviolet detectors
NASA's abstract says AlGaN detectors can be designed to reject solar radiation 1000 times better than silicon detectors at a 325 nm cut-off.
UV sensing instruments
A NASA Tech Briefs article lists plume measurements, flame sensing, UV lidar, biological agent detection and airborne particle sizing as uses of AlGaN UV detectors.
Recipe
AlxGa1-xN, an alloy of aluminium nitride (AlN) and gallium nitride (GaN); x is the aluminium fraction
AlGaN is an alloy of aluminium nitride (AlN) and gallium nitride (GaN), written AlxGa1-xN. The aluminium fraction x sets the bandgap. The 2006 article says the detector layers were grown on 2 inch c-plane sapphire substrates.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Aluminium Al | not stated | Sets the bandgap. The NASA abstract gives 6.2 eV for pure AlN, the wide end of the alloy range. |
| Gallium Ga | not stated | Sets the bandgap. The NASA abstract gives 3.4 eV for pure GaN, the narrow end of the alloy range. |
| Nitrogen N | not stated | Bonds to the metal atoms in the nitride lattice. The sources read give no further detail. |
Weight shares are as printed in the sources.
What it can do
Bandgap tuning
3.4 to 6.2 eV
measured
The NASA abstract gives direct bandgaps of 3.4 eV for GaN and 6.2 eV for AlN, the two ends of the alloy range. The bandgap of the alloy at a given aluminium fraction is not printed in the sources read.
Solar-blind cut-off
280 nm
measured
The 2006 article says an Al0.47Ga0.53N absorber gives a 280 nm cut-off, and that the array operates below 280 nm, the solar-blind band.
Solar rejection
1000x
measured
NASA gives 1000 times better solar rejection than silicon detectors at a 325 nm cut-off, and a NASA Tech Briefs article repeats the 1000x figure.
Quantum efficiency
48%
measured
The 2006 article gives a 48% peak quantum efficiency at zero bias for an AlGaN photodiode, and more than 50% at 270 nm.
How it compares
AlGaN covers a tunable part of the ultraviolet that GaN alone cannot, because the aluminium fraction moves the bandgap from the 365 nm GaN cut-off down toward the 200 nm AlN end (NASA abstract). Silicon is the reference for solar rejection: NASA gives 1000 times better rejection for AlGaN than silicon at a 325 nm cut-off. The sources read give no density or mobility for the alloy. The thermal conductivity and lattice values at x = 0.5 are first-principles calculations, so they are not ranked against measured values for other materials.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details.
| Measurement | AlGaN |
|---|---|
| Capacity and energy | |
| Lowest nitrogen Frenkel pair formation energy, AlGaN with 25% Al | 6.57 eV17 |
| Thermal behavior and safety | |
| Thermal conductivity along [100], Al0.5Ga0.5N (first-principles) | 186.7 W/(m·K)13 |
| Thermal conductivity along [001], Al0.5Ga0.5N (first-principles) | 165.2 W/(m·K)14 |
| Thermal conductivity along [111], Al0.5Ga0.5N (first-principles) | 177.6 W/(m·K)15 |
| Other measurements | |
| Direct bandgap, GaN to AlN end members (alloy range) | 3.4 to 6.2 eV1 |
| Tunable detection range of AlGaN alloys | 200 to 365 nm2 |
| Solar-blind cut-off of the AlGaN absorber | 280 nm3 |
| Short-wavelength edge of the photosensitivity bandCut-on wavelength printed in the article | 260 nm |
| Peak quantum efficiency at zero bias | 48 %4 |
| Quantum efficiency at 270 nm | > 50 %5 |
| Quantum efficiency without reflection loss | 52.3 %6 |
| Solar radiation rejection compared with silicon (NASA Tech Briefs) | 1000 x7 |
| Cut-off wavelength of an AlGaN UV detector design (planetary)Cut-off printed in the NASA abstract | 325 nm8 |
| Current responsivity at 360 nm, 0 VFigure printed in the NASA Tech Briefs article | 0.13 A/W9 |
| Peak quantum efficiency at 360 nm, -0.5 VFigure printed in the NASA Tech Briefs article | 50 %10 |
| Lattice constant a, Al0.50Ga0.50N (DFT) | 3.172 Å11 |
| Lattice constant c, Al0.50Ga0.50N (DFT) | 5.101 Å12 |
| Bulk modulus, Al0.5Ga0.5N (machine-learning potential) | 204 GPa16 |
Why choose it, and why not
Good for
- Solar-blind ultraviolet detection, where the 2006 article reports operation below 280 nm.
- Planetary ultraviolet instruments, where NASA reports 1000 times better solar rejection than silicon.
Watch out for
- Sources disagree on the cut-off: 280 nm for the 2006 BAE Systems absorber and 325 nm for the NASA design. Both are printed.
- The NASA Tech Briefs photodiode has a 365 nm cut-off, which matches GaN, so its numbers are for a different design.
- No density, melting point, mobility or breakdown field for the alloy was found in any source read this run. The thermal conductivity and bulk modulus rows are first-principles or machine-learning calculations, not measurements.
- The one failure entry is calculated, not tested: a nitrogen Frenkel pair energy from the machine-learning study, with no irradiation test on AlGaN read.
AlGaN is a tunable ultraviolet semiconductor whose bandgap range is documented at its two ends, 3.4 eV for GaN and 6.2 eV for AlN. The device numbers are results from detectors, and the alloy constants are calculated at x = 0.5, so the material data are still thin, with no measured density, melting point or mobility for the alloy found yet.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Direct bandgap, GaN to AlN end members (alloy range) | Direct bandgaps printed in the NASA abstract for three nitrides, read as InN, GaN and AlN in that order; the 3.4 eV and 6.2 eV values are the GaN and AlN entries | composition AlxGa1-xN from x = 0 (GaN) to x = 1 (AlN)temperature not stated in the abstractbasis end-member values from the abstract; the bandgap at intermediate x is not given in this source | — |
| 2 | Tunable detection range of AlGaN alloys | Range printed in a 2006 trade article on AlGaN filter-free detection; the NASA abstract gives 200 nm for AlN and 365 nm for GaN as the matching ends | basis tunable direct-bandgap range quoted for AlGaN alloyscomposition AlGaN across the alloy range | — |
| 3 | Solar-blind cut-off of the AlGaN absorber | Cut-off wavelength printed in the article for the absorber layer | absorber Al0.47Ga0.53Ndevice back-illuminated AlGaN hybrid focal-plane array developed at BAE Systems, Lexington, MAoperation solar-blind, below 280 nm | The NASA abstract gives 325 nm for its AlGaN design (see the 325 nm row below). Both figures are printed; this profile does not choose between them. |
| 4 | Peak quantum efficiency at zero bias | Peak quantum efficiency printed in the article's detector performance paragraph | bias zero biasdevice AlGaN photodiode described in the articlewavelength not stated in the fetched article text | — |
| 5 | Quantum efficiency at 270 nm | Printed as more than 50% at 270 nm in the article | wavelength 270 nmdevice solar-blind AlGaN array described in the article | — |
| 6 | Quantum efficiency without reflection loss | Corrected figure stated by the article's authors; not a direct measurement in the source | device UT diode described in the articlebasis figure the authors state would apply with no reflection loss | — |
| 7 | Solar radiation rejection compared with silicon (NASA Tech Briefs) | Figure printed in the NASA Goddard Tech Briefs article dated October 1, 2010 | reference silicon-based detectorsbasis stated for AlGaN UV detectors in the NASA Tech Briefs article | — |
| 8 | Cut-off wavelength of an AlGaN UV detector design (planetary) | — | basis cut-off named in the same sentence as the 1000x rejection figurereference silicon-based detectors | Conflicts with the 280 nm solar-blind cut-off printed in the 2006 article. Both are kept; no source reconciles them. |
| 9 | Current responsivity at 360 nm, 0 V | — | wavelength 360 nmbias 0 Vdevice AlGaN UV PIN photodiode as described in the NASA Tech Briefs article | The same article gives a 365 nm long-wavelength cut-off for this device, which matches the GaN value in the NASA abstract. The composition of this device is not stated, so it is not the 280 nm absorber. |
| 10 | Peak quantum efficiency at 360 nm, -0.5 V | — | wavelength 360 nmbias -0.5 Vdevice same AlGaN photodiode as the 0.13 A/W responsivity row | Same device caveat as the responsivity row: its cut-off is printed as 365 nm. |
| 11 | Lattice constant a, Al0.50Ga0.50N (DFT) | DFT with the generalized gradient approximation (GGA) on the wurtzite cell, as stated in the paper's abstract | composition Al0.50Ga0.50N (x = 0.5)structure wurtzitebasis density functional theory calculation in the paper, listed as Present Work | — |
| 12 | Lattice constant c, Al0.50Ga0.50N (DFT) | DFT with the generalized gradient approximation (GGA) on the wurtzite cell, as stated in the paper's abstract | composition Al0.50Ga0.50N (x = 0.5)structure wurtzitebasis density functional theory calculation in the paper, listed as Present Work | — |
| 13 | Thermal conductivity along [100], Al0.5Ga0.5N (first-principles) | First-principles calculation of anisotropic thermal conductivity, printed in the paper's abstract | composition Al0.5Ga0.5Ndirection [100]temperature 300 K | — |
| 14 | Thermal conductivity along [001], Al0.5Ga0.5N (first-principles) | First-principles calculation of anisotropic thermal conductivity, printed in the paper's abstract | composition Al0.5Ga0.5Ndirection [001]temperature 300 K | — |
| 15 | Thermal conductivity along [111], Al0.5Ga0.5N (first-principles) | First-principles calculation of anisotropic thermal conductivity, printed in the paper's abstract | composition Al0.5Ga0.5Ndirection [111]temperature 300 K | — |
| 16 | Bulk modulus, Al0.5Ga0.5N (machine-learning potential) | Elastic constants and bulk modulus B from the machine-learning potential at the ground state, as printed in the paper | composition Al0.5Ga0.5N (x = 0.5), wurtzitebasis prediction from a machine-learning interatomic potential, labelled This work in Table I | — |
| 17 | Lowest nitrogen Frenkel pair formation energy, AlGaN with 25% Al | Machine-learning interatomic potential calculation, as stated in the paper's text; not an irradiation experiment | composition 25% Al (AlxGa1-xN, x = 0.25)defect nitrogen Frenkel pair (a vacancy plus an interstitial), lowest-energy configuration in the energy histogram | — |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
No safety data sheet or GHS entry for AlGaN itself was read. PubChem's GHS entry for the GaN end member gives H317, a skin sensitiser warning.
- Dust
- Handle wafers and powder with care until a supplier safety data sheet for the specific product has been checked.
- Skin contact
- PubChem's aggregated GHS entry for gallium nitride lists H317, may cause an allergic skin reaction, and signal word Warning.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Nitrogen Frenkel pair defects in AlGaN under radiation or high temperature | Irradiation or high-temperature processing (calculated only; the paper does not test irradiation)The paper calculates that low-energy nitrogen Frenkel pairs exist in AlGaN, with the lowest at 6.57 eV at 25% Al, and states that under irradiation or high-temperature processing these configurations may form preferentially and dominate the early defect population. |
Supply and geography
How common the raw materials are and where they come from.
Gallium
- Top producers (2025)
- China 99%
- Critical mineral lists
- US: listed, EU: listed
- Recycling
- USGS: old scrap recovery is none. Substantial new scrap from GaAs device manufacture was reprocessed to high-purity gallium at one New York facility.
- Substitutes
- USGS: in many defense-related applications no effective substitutes exist for GaAs and GaN.
Aluminium (USGS spelling: aluminum)
- Top producers (2025)
- China 60.8%, India 5.7%, Russia 5.3%, Canada 4.5%
- Critical mineral lists
- US: listed, EU: listed
- Recycling
- USGS: about 3.6 million tons of aluminum were recovered from purchased scrap in the United States in 2025.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
spore: profile
id: aluminium-gallium-nitride
spore_version: 0.2
family: nitride-semiconductors
name: Aluminium gallium nitride
abbreviation: AlGaN
role: wide-bandgap semiconductor alloy
category: semiconductors
type: gan
summary: |
Aluminium gallium nitride (AlGaN) is an alloy of aluminium nitride and gallium nitride, written AlxGa1-xN. NASA gives the direct bandgaps of GaN and AlN as 3.4 eV and 6.2 eV, so the aluminium fraction x sets a bandgap anywhere between those two values. A 2006 trade article reports a back-illuminated AlGaN array from BAE Systems with a 280 nm solar-blind cut-off, using an Al0.47Ga0.53N absorber. NASA reports that AlGaN detectors can be designed to reject solar radiation about 1000 times better than silicon detectors at a 325 nm cut-off. No density or melting point for the alloy was found in the sources read for this profile. Calculated alloy values at x = 0.5 are listed: lattice constants (DFT), a first-principles thermal conductivity, and a bulk modulus from a machine-learning potential. These are calculations, not measurements.
best_for: Ultraviolet detectors that must ignore sunlight, such as solar-blind work below 280 nm (BAE Systems) and planetary UV instruments (NASA Goddard)
weakest_at: Few material constants for the alloy were found. The numbers here are mostly device results, and the cut-off figures differ between sources (see gaps)
identity:
formula: AlxGa1-xN, an alloy of aluminium nitride (AlN) and gallium nitride (GaN); x is the aluminium fraction
source: wiki-algan
where: Lead section (formula AlxGa1-xN; alloy of AlN and GaN)
tags:
applications:
- optics-and-cameras
properties:
- benchmark: bandgap
label: Direct bandgap, GaN to AlN end members (alloy range)
value: 3.4
value_high: 6.2
bound: range
unit: eV
scope: material
conditions:
composition: AlxGa1-xN from x = 0 (GaN) to x = 1 (AlN)
temperature: not stated in the abstract
basis: end-member values from the abstract; the bandgap at intermediate x is not given in this source
method: Direct bandgaps printed in the NASA abstract for three nitrides, read as InN, GaN and AlN in that order; the 3.4 eV and 6.2 eV values are the GaN and AlN entries
status: ground
source: ntrs-2012
where: Abstract, sentence giving direct bandgaps 0.8, 3.4 and 6.2 eV, respectively
- benchmark: cutoff_wavelength
label: Tunable detection range of AlGaN alloys
value: 200
value_high: 365
bound: range
unit: nm
scope: material
conditions:
basis: tunable direct-bandgap range quoted for AlGaN alloys
composition: AlGaN across the alloy range
method: Range printed in a 2006 trade article on AlGaN filter-free detection; the NASA abstract gives 200 nm for AlN and 365 nm for GaN as the matching ends
status: ground
source: compoundsemi-2006
where: Article text on the tunable direct bandgap (section not labelled in the fetched text)
- benchmark: cutoff_wavelength
label: Solar-blind cut-off of the AlGaN absorber
value: 280
unit: nm
scope: material
conditions:
absorber: Al0.47Ga0.53N
device: back-illuminated AlGaN hybrid focal-plane array developed at BAE Systems, Lexington, MA
operation: solar-blind, below 280 nm
method: Cut-off wavelength printed in the article for the absorber layer
status: ground
note: The NASA abstract gives 325 nm for its AlGaN design (see the 325 nm row below). Both figures are printed; this profile does not choose between them.
source: compoundsemi-2006
where: Article text on the Al0.47Ga0.53N absorber and solar-blind operation below 280 nm
- benchmark: cut_on_wavelength
label: Short-wavelength edge of the photosensitivity band
value: 260
unit: nm
scope: material
conditions:
device: back-illuminated AlGaN hybrid focal-plane array (BAE Systems)
band: 260 to 280 nm photosensitivity
method: Cut-on wavelength printed in the article
status: ground
source: compoundsemi-2006
where: Article text on the 260 to 280 nm photosensitivity band
- benchmark: quantum_efficiency_peak
label: Peak quantum efficiency at zero bias
value: 48
unit: '%'
scope: material
conditions:
bias: zero bias
device: AlGaN photodiode described in the article
wavelength: not stated in the fetched article text
method: Peak quantum efficiency printed in the article's detector performance paragraph
status: ground
source: compoundsemi-2006
where: Article text, detector performance paragraph (48% peak quantum efficiency at zero bias)
- benchmark: quantum_efficiency
label: Quantum efficiency at 270 nm
value: 50
bound: lower
unit: '%'
scope: material
conditions:
wavelength: 270 nm
device: solar-blind AlGaN array described in the article
method: Printed as more than 50% at 270 nm in the article
status: ground
source: compoundsemi-2006
where: Article text, detector performance paragraph (quantum efficiency of more than 50% at 270 nm)
- benchmark: quantum_efficiency
label: Quantum efficiency without reflection loss
value: 52.3
unit: '%'
scope: material
conditions:
device: UT diode described in the article
basis: figure the authors state would apply with no reflection loss
method: Corrected figure stated by the article's authors; not a direct measurement in the source
status: calculated
source: compoundsemi-2006
where: Article text, quantum efficiency paragraph (the UT diode quantum efficiency would have been 52.3%)
- benchmark: solar_rejection_ratio
label: Solar radiation rejection compared with silicon (NASA Tech Briefs)
value: 1000
unit: x
scope: material
conditions:
reference: silicon-based detectors
basis: stated for AlGaN UV detectors in the NASA Tech Briefs article
method: Figure printed in the NASA Goddard Tech Briefs article dated October 1, 2010
status: ground
source: techbriefs-gsc15673
where: Article body, AlGaN solar radiation rejection compared with silicon
- benchmark: cutoff_wavelength
label: Cut-off wavelength of an AlGaN UV detector design (planetary)
value: 325
unit: nm
scope: material
conditions:
basis: cut-off named in the same sentence as the 1000x rejection figure
reference: silicon-based detectors
method: Cut-off printed in the NASA abstract
status: ground
note: Conflicts with the 280 nm solar-blind cut-off printed in the 2006 article. Both are kept; no source reconciles them.
source: ntrs-2012
where: Abstract, sentence on AlGaN UV rejection compared with Si-based detectors
- benchmark: responsivity
label: Current responsivity at 360 nm, 0 V
value: 0.13
unit: A/W
scope: material
conditions:
wavelength: 360 nm
bias: 0 V
device: AlGaN UV PIN photodiode as described in the NASA Tech Briefs article
method: Figure printed in the NASA Tech Briefs article
status: ground
note: The same article gives a 365 nm long-wavelength cut-off for this device, which matches the GaN value in the NASA abstract. The composition of this device is not stated, so it is not the 280 nm absorber.
source: techbriefs-gsc15673
where: Article body, performance figures for the AlGaN photodiode
- benchmark: quantum_efficiency_peak
label: Peak quantum efficiency at 360 nm, -0.5 V
value: 50
unit: '%'
scope: material
conditions:
wavelength: 360 nm
bias: '-0.5 V'
device: same AlGaN photodiode as the 0.13 A/W responsivity row
method: Figure printed in the NASA Tech Briefs article
status: ground
note: 'Same device caveat as the responsivity row: its cut-off is printed as 365 nm.'
source: techbriefs-gsc15673
where: Article body, performance figures for the AlGaN photodiode
- benchmark: lattice_constant_a
label: Lattice constant a, Al0.50Ga0.50N (DFT)
value: 3.1719
unit: Å
scope: material
conditions:
composition: Al0.50Ga0.50N (x = 0.5)
structure: wurtzite
basis: density functional theory calculation in the paper, listed as Present Work
method: DFT with the generalized gradient approximation (GGA) on the wurtzite cell, as stated in the paper's abstract
status: calculated
source: arxiv-lattice-0811
where: Table I, Al0.50 Ga0.50 N row, a column
- benchmark: lattice_constant_c
label: Lattice constant c, Al0.50Ga0.50N (DFT)
value: 5.1012
unit: Å
scope: material
conditions:
composition: Al0.50Ga0.50N (x = 0.5)
structure: wurtzite
basis: density functional theory calculation in the paper, listed as Present Work
method: DFT with the generalized gradient approximation (GGA) on the wurtzite cell, as stated in the paper's abstract
status: calculated
source: arxiv-lattice-0811
where: Table I, Al0.50 Ga0.50 N row, c column
- benchmark: thermal_conductivity
label: Thermal conductivity along [100], Al0.5Ga0.5N (first-principles)
value: 186.74
unit: W/(m·K)
scope: material
conditions:
composition: Al0.5Ga0.5N
direction: '[100]'
temperature: 300 K
method: First-principles calculation of anisotropic thermal conductivity, printed in the paper's abstract
status: calculated
source: mpm-thermal-2022
where: Abstract, Al0.5Ga0.5N row of the thermal conductivity table, [100] column
- benchmark: thermal_conductivity
label: Thermal conductivity along [001], Al0.5Ga0.5N (first-principles)
value: 165.24
unit: W/(m·K)
scope: material
conditions:
composition: Al0.5Ga0.5N
direction: '[001]'
temperature: 300 K
method: First-principles calculation of anisotropic thermal conductivity, printed in the paper's abstract
status: calculated
source: mpm-thermal-2022
where: Abstract, Al0.5Ga0.5N row of the thermal conductivity table, [001] column
- benchmark: thermal_conductivity
label: Thermal conductivity along [111], Al0.5Ga0.5N (first-principles)
value: 177.62
unit: W/(m·K)
scope: material
conditions:
composition: Al0.5Ga0.5N
direction: '[111]'
temperature: 300 K
method: First-principles calculation of anisotropic thermal conductivity, printed in the paper's abstract
status: calculated
source: mpm-thermal-2022
where: Abstract, Al0.5Ga0.5N row of the thermal conductivity table, [111] column
- benchmark: bulk_modulus
label: Bulk modulus, Al0.5Ga0.5N (machine-learning potential)
value: 204
unit: GPa
scope: material
conditions:
composition: Al0.5Ga0.5N (x = 0.5), wurtzite
basis: prediction from a machine-learning interatomic potential, labelled This work in Table I
method: Elastic constants and bulk modulus B from the machine-learning potential at the ground state, as printed in the paper
status: calculated
source: arxiv-elastic-2510
where: Table I, Al0.5 Ga0.5 N row, B column
- benchmark: frenkel_pair_formation_energy
label: Lowest nitrogen Frenkel pair formation energy, AlGaN with 25% Al
value: 6.57
unit: eV
scope: material
conditions:
composition: 25% Al (AlxGa1-xN, x = 0.25)
defect: nitrogen Frenkel pair (a vacancy plus an interstitial), lowest-energy configuration in the energy histogram
method: Machine-learning interatomic potential calculation, as stated in the paper's text; not an irradiation experiment
status: calculated
source: arxiv-elastic-2510
where: Section B (Frenkel Pair Formation Energy), paragraph on the 25% Al energy histogram
corrosion: []
risks:
hazards:
- text: 'PubChem GHS for gallium nitride, the GaN end member (not AlGaN itself): H317, May cause an allergic skin reaction, with signal word Warning, reported in 97.8% of aggregated company notifications. 2.2% of reports say the chemical does not meet GHS hazard criteria.'
ghs:
- H317
source: pubchem-gan
where: Safety and Hazards, Hazards Identification, GHS Classification (CID 117559)
failure_risks:
- mode: Nitrogen Frenkel pair defects in AlGaN under radiation or high temperature
trigger: Irradiation or high-temperature processing (calculated only; the paper does not test irradiation)
consequence: The paper calculates that low-energy nitrogen Frenkel pairs exist in AlGaN, with the lowest at 6.57 eV at 25% Al, and states that under irradiation or high-temperature processing these configurations may form preferentially and dominate the early defect population.
source: arxiv-elastic-2510
where: Section B, Frenkel pair formation energy, and the implications paragraph
side_effects: []
handling: []
mitigations: []
uses:
- application: optics-and-cameras
device: Back-illuminated solar-blind UV focal-plane array (256 x 256 pixels)
example: The 2006 article describes BAE Systems' first solar-blind 256 x 256 AlGaN back-illuminated hybrid UV focal-plane arrays, with 30 um x 30 um unit cells and photosensitivity in the 260 to 280 nm band.
source: compoundsemi-2006
where: Article text on the 256 x 256 array and unit cells
- application: optics-and-cameras
device: UV detector for planetary missions
example: NASA Goddard's abstract, titled for next-generation ultraviolet planetary missions, says AlGaN detectors can be designed to give 1000x solar radiation rejection at a 325 nm cut-off, compared with Si-based detectors.
source: ntrs-2012
where: Title and abstract
- application: optics-and-cameras
device: UV sensing instruments for plume, flame, lidar and bio-agent work
example: The NASA Tech Briefs article lists AlGaN UV detector uses as plume measurements, flame sensing, UV lidar, biological agent detection, and airborne particulate size and velocity measurement.
source: techbriefs-gsc15673
where: Article body, applications paragraph
supply:
- subject: Gallium
producers:
- country: China
share_percent: 99
year: 2025
critical_lists:
- list: 'USGS 2025 List of Critical Minerals (entry: Gallium, used in semiconductors)'
listed: true
- list: 'EU critical raw materials list (Regulation (EU) 2024/1252, entry: Gallium)'
listed: true
recycling: 'USGS: old scrap recovery is none. Substantial new scrap from GaAs device manufacture was reprocessed to high-purity gallium at one New York facility.'
substitutes:
- 'USGS: in many defense-related applications no effective substitutes exist for GaAs and GaN.'
source: usgs-mcs2026-gallium
where: Events, Trends, and Issues (China accounted for 99% of worldwide primary low-purity gallium production); Recycling; Substitutes; Salient Statistics table (net import reliance 100 in every year listed). The 99% is for primary low-purity gallium, not for refined gallium used in AlGaN.
- subject: 'Aluminium (USGS spelling: aluminum)'
producers:
- country: China
share_percent: 60.8
year: 2025
- country: India
share_percent: 5.7
year: 2025
- country: Russia
share_percent: 5.3
year: 2025
- country: Canada
share_percent: 4.5
year: 2025
critical_lists:
- list: 'USGS 2025 List of Critical Minerals (entry: Aluminum, used in almost all sectors of the economy)'
listed: true
- list: EU critical raw materials list (aluminium merged into the Bauxite entry, per the European Commission page)
listed: true
recycling: 'USGS: about 3.6 million tons of aluminum were recovered from purchased scrap in the United States in 2025.'
substitutes: []
source: usgs-mcs2026-aluminum
where: World smelter production table, 2025e (shares calculated by Space Mushroom from China 45,000, India 4,200, Russia 3,900 and Canada 3,300 against the printed world total of 74,000, rounded); Recycling. Aluminium is the feedstock for the aluminium part of the alloy.
documents:
- title: 'NASA NTRS 20120016988: GaN-Based Detector Enabling Technology for Next Generation Ultraviolet Planetary Missions'
type: report
url: https://ntrs.nasa.gov/citations/20120016988
year: 2012
- title: 'USGS Mineral Commodity Summaries 2026: Gallium'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Aluminum'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf
year: 2026
- title: NASA Tech Briefs article, reference GSC-15673-1
type: report
url: https://www.techbriefs.com/component/content/article/8640-gsc-15673-1
year: 2010
- title: 'arXiv 0811.0380: Ab initio calculation of structural and electronic properties of AlxGa1-xN and InxGa1-xN alloys'
type: paper
url: https://arxiv.org/pdf/0811.0380
year: 2008
- title: 'arXiv 2510.25912: Evaluation of Structural Properties and Defect Energetics in AlxGa1-xN Alloys'
type: paper
url: https://arxiv.org/pdf/2510.25912
year: 2025
- title: 'Materials Physics and Mechanics 49(1): First-principles study of anisotropic thermal conductivity of GaN, AlN, and Al0.5Ga0.5N'
type: paper
url: https://mpm.spbstu.ru/article/2022.89.7/
year: 2022
- title: 'PubChem CID 117559: Gallium nitride, GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/Gallium-nitride
year: 2026
gaps:
- Density, melting or decomposition temperature, electron mobility and breakdown field for AlGaN were not found in any source read in this run. The lattice constants, thermal conductivity and bulk modulus in the properties list are calculated values at x = 0.5, not measurements. The arXiv 0811.0380 table also gives lattice constants at x = 0.25 and 0.75, which are not added.
- The Ioffe Institute basic-parameter page for AlGaN could not be opened in this run (self-signed certificate error), so its band-gap bowing and thermal values are not used. The Springer and Balandin group AlGaN pages and a DOAJ record for a 270 nm AlGaN LED irradiation paper could not be opened either (redirect, DNS failure and a Cloudflare block).
- No safety data sheet or GHS entry for AlGaN itself was found. The hazard entry is for the GaN end member from PubChem. The Wikipedia safety note (toxicology not fully studied; dust irritates skin, eyes and lungs) was not used as a source because the brief limits Wikipedia to composition and history. A supplier SDS for AlGaN wafers or powder is needed.
- No corrosion, oxidation, ageing or humidity test for AlGaN was read, so the corrosion list is empty.
- The one failure entry is a calculated defect energy from a machine-learning potential. No irradiation test or device-level failure data for AlGaN was read. The source gives no severity, so the failure entry has no severity field.
- Lattice constants a and c and the frenkel_pair_formation_energy benchmark are short snake_case names not in spores/property-canon.yaml. Elastic constants C11, C12, C13, C33 and C44 for Al0.5Ga0.5N (2510.25912 Table I) are not added, only the bulk modulus B.
- AlGaN/GaN high-electron-mobility transistor use is named only in Wikipedia. No HEMT property (mobility, carrier density, power or frequency) was read.
- The 280 nm solar-blind cut-off (2006 article) and the 325 nm cut-off (NASA abstract) are both printed. No source reconciles them.
- The 48% peak quantum efficiency is printed without a wavelength in the fetched article text.
- The NASA Tech Briefs device is called AlGaN but has a 365 nm cut-off, and its composition is not stated. Its responsivity and quantum efficiency rows are kept with that caveat.
- No atomic weight for aluminium, gallium or nitrogen was read in a fetched source, so the recipe parts carry no atomic weights.
- No standard designation (UNS, EN, CAS) exists for the alloy in any source read; AlGaN is a composition family, not one grade.
- Crustal abundance of gallium and aluminium was not read in this run.
- Benchmark names cutoff_wavelength, cut_on_wavelength, quantum_efficiency, quantum_efficiency_peak, responsivity and solar_rejection_ratio are short snake_case names. None is in spores/property-canon.yaml, and bandgap is used as in the GaN profile.
- The 99% gallium share is a USGS statement about primary low-purity production. The aluminium shares are calculated by Space Mushroom from smelter production, not taken from a printed share. - "The NASA abstract's 1000x rejection figure is read from the fetched summary. The PDF text layer prints it as I OOOx (OCR), so the value check could not match it and the figure has no verified property row. The NASA Tech Briefs row with the same figure could not be read by the value check either."
sources:
ntrs-2012:
title: GaN-Based Detector Enabling Technology for Next Generation Ultraviolet Planetary Missions
id: NTRS 20120016988; GSFC.CPR.6772.2012; IPM-2012 (October 10, 2012)
url: https://ntrs.nasa.gov/citations/20120016988
year: 2012
kind: report
license: public domain (NASA)
compoundsemi-2006:
title: AlGaN provides filter-free detection (Compound Semiconductor, article 84128)
id: Compound Semiconductor, published 27 June 2006
url: https://compoundsemiconductor.net/article/84128/AlGaN_provides_filter-free_detection
year: 2006
kind: web
license: trade article, cited not reproduced
techbriefs-gsc15673:
title: NASA Tech Briefs article, reference GSC-15673-1 (AlGaN solar-blind UV detector)
id: GSC-15673-1; NASA Tech Briefs Vol. 34 No. 10 (October 1, 2010)
url: https://www.techbriefs.com/component/content/article/8640-gsc-15673-1
year: 2010
kind: web
license: public domain (NASA text)
wiki-algan:
title: Aluminium gallium nitride (Wikipedia), used for composition only
id: Wikipedia, lead section
url: https://en.wikipedia.org/wiki/Aluminium_gallium_nitride
year: 2026
kind: web
license: CC BY-SA 4.0
usgs-mcs2026-gallium:
title: Mineral Commodity Summaries 2026, Gallium
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-mcs2026-aluminum:
title: Mineral Commodity Summaries 2026, Aluminum
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-crit2025:
title: About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)
id: Final 2025 List of Critical Minerals
url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
year: 2025
kind: web
license: public domain (USGS)
ec-crm:
title: Critical raw materials (European Commission, Regulation (EU) 2024/1252)
id: Regulation (EU) 2024/1252
url: https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en
year: 2024
kind: web
license: European Commission web page
arxiv-lattice-0811:
title: Ab initio calculation of structural and electronic properties of AlxGa1-xN and InxGa1-xN alloys
id: arXiv:0811.0380; E. López-Apreza, J. Arriaga and D. Olguín (2008)
url: https://arxiv.org/pdf/0811.0380
year: 2008
kind: paper
license: arXiv preprint
arxiv-elastic-2510:
title: Evaluation of Structural Properties and Defect Energetics in AlxGa1-xN Alloys
id: arXiv:2510.25912; F. Reza, B. Chen and M. Jin (Pennsylvania State University, 2025)
url: https://arxiv.org/pdf/2510.25912
year: 2025
kind: paper
license: arXiv preprint
mpm-thermal-2022:
title: First-principles study of anisotropic thermal conductivity of GaN, AlN, and Al0.5Ga0.5N
id: Materials Physics and Mechanics 49(1), pp. 97-107; D. Hvazdouski, M.S. Baranava and V.R. Stempitsky (2022)
url: https://mpm.spbstu.ru/article/2022.89.7/
year: 2022
kind: paper
license: not checked
pubchem-gan:
title: Gallium nitride, PubChem CID 117559, GHS classification
id: PubChem CID 117559 (Gallium nitride)
url: https://pubchem.ncbi.nlm.nih.gov/compound/Gallium-nitride
year: 2026
kind: database
license: PubChem public database
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 18
unreachable: 4
caveats: 3
note: Written by an AI assistant on 2026-11-01 from the NASA, trade, alloy-calculation and USGS pages, and deepened the same day with arXiv tables, an MPM first-principles paper and PubChem GHS data. Values are copied as printed. The Ioffe AlGaN page, the Springer and Balandin pages and a DOAJ record could not be opened. The NASA full text was read from a fetch summary.
story:
recipe:
line: AlGaN is an alloy of aluminium nitride (AlN) and gallium nitride (GaN), written AlxGa1-xN. The aluminium fraction x sets the bandgap. The 2006 article says the detector layers were grown on 2 inch c-plane sapphire substrates.
parts:
- name: Aluminium
symbol: Al
share_of_metal_sites: x
role: Sets the bandgap. The NASA abstract gives 6.2 eV for pure AlN, the wide end of the alloy range.
- name: Gallium
symbol: Ga
share_of_metal_sites: 1 - x
role: Sets the bandgap. The NASA abstract gives 3.4 eV for pure GaN, the narrow end of the alloy range.
- name: Nitrogen
symbol: 'N'
role: Bonds to the metal atoms in the nitride lattice. The sources read give no further detail.
risk_groups:
- title: For people
verdict: GaN end member carries H317 (may cause an allergic skin…
lead: No safety data sheet or GHS entry for AlGaN itself was read. PubChem's GHS entry for the GaN end member gives H317, a skin sensitiser warning.
points:
- label: Dust
line: Handle wafers and powder with care until a supplier safety data sheet for the specific product has been checked.
- label: Skin contact
line: PubChem's aggregated GHS entry for gallium nitride lists H317, may cause an allergic skin reaction, and signal word Warning.
why: Aluminium gallium nitride (AlGaN) is a semiconductor that can be tuned across the ultraviolet. NASA gives direct bandgaps of 3.4 eV for GaN and 6.2 eV for AlN, and the aluminium fraction sets the value in between. A detector that absorbs only below a chosen wavelength can ignore the visible and near-visible light of the Sun. NASA Goddard works on this family of detectors for next-generation ultraviolet planetary missions.
uses:
- where: Solar-blind ultraviolet focal-plane arrays
line: A 2006 article describes BAE Systems' 256 x 256 back-illuminated AlGaN hybrid arrays, with an absorber that cuts off at 280 nm and a photosensitivity band of 260 to 280 nm.
- where: Planetary ultraviolet detectors
line: NASA's abstract says AlGaN detectors can be designed to reject solar radiation 1000 times better than silicon detectors at a 325 nm cut-off.
- where: UV sensing instruments
line: A NASA Tech Briefs article lists plume measurements, flame sensing, UV lidar, biological agent detection and airborne particle sizing as uses of AlGaN UV detectors.
can_do:
- label: Bandgap tuning
benchmark: bandgap
value: 3.4 to 6.2 eV
line: The NASA abstract gives direct bandgaps of 3.4 eV for GaN and 6.2 eV for AlN, the two ends of the alloy range. The bandgap of the alloy at a given aluminium fraction is not printed in the sources read.
- label: Solar-blind cut-off
benchmark: cutoff_wavelength
value: 280 nm
line: The 2006 article says an Al0.47Ga0.53N absorber gives a 280 nm cut-off, and that the array operates below 280 nm, the solar-blind band.
- label: Solar rejection
benchmark: solar_rejection_ratio
value: 1000x
line: NASA gives 1000 times better solar rejection than silicon detectors at a 325 nm cut-off, and a NASA Tech Briefs article repeats the 1000x figure.
- label: Quantum efficiency
benchmark: quantum_efficiency_peak
value: 48%
line: The 2006 article gives a 48% peak quantum efficiency at zero bias for an AlGaN photodiode, and more than 50% at 270 nm.
compare: 'AlGaN covers a tunable part of the ultraviolet that GaN alone cannot, because the aluminium fraction moves the bandgap from the 365 nm GaN cut-off down toward the 200 nm AlN end (NASA abstract). Silicon is the reference for solar rejection: NASA gives 1000 times better rejection for AlGaN than silicon at a 325 nm cut-off. The sources read give no density or mobility for the alloy. The thermal conductivity and lattice values at x = 0.5 are first-principles calculations, so they are not ranked against measured values for other materials.'
compare_rows:
- label: Bandgap across the alloy range
benchmark: bandgap
- label: Solar-blind cut-off
benchmark: cutoff_wavelength
- label: Quantum efficiency at peak
benchmark: quantum_efficiency_peak
handling:
- No handling data for AlGaN were found in the sources read this run. Use the supplier safety data sheet for the wafer or powder you buy.
- Keep the wafer or powder dry and closed until use, and avoid dust, pending a product SDS.
good_for:
- Solar-blind ultraviolet detection, where the 2006 article reports operation below 280 nm.
- Planetary ultraviolet instruments, where NASA reports 1000 times better solar rejection than silicon.
watch_out:
- 'Sources disagree on the cut-off: 280 nm for the 2006 BAE Systems absorber and 325 nm for the NASA design. Both are printed.'
- The NASA Tech Briefs photodiode has a 365 nm cut-off, which matches GaN, so its numbers are for a different design.
- No density, melting point, mobility or breakdown field for the alloy was found in any source read this run. The thermal conductivity and bulk modulus rows are first-principles or machine-learning calculations, not measurements.
- 'The one failure entry is calculated, not tested: a nitrogen Frenkel pair energy from the machine-learning study, with no irradiation test on AlGaN read.'
verdict: AlGaN is a tunable ultraviolet semiconductor whose bandgap range is documented at its two ends, 3.4 eV for GaN and 6.2 eV for AlN. The device numbers are results from detectors, and the alloy constants are calculated at x = 0.5, so the material data are still thin, with no measured density, melting point or mobility for the alloy found yet.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
Updated