GaAs
GaAs is a III-V semiconductor single crystal with high strength and low absorption at 10.6 µm, supplied as semi-insulating LEC and VGF material, n-type (N-GAAS) and polycrystalline blanks.
Reference datasheet — GaAs is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SI-LEC condition
GaAs tempers and conditions
GaAs is supplied in 4 conditions, soft to hard. SI-LEC is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Poly-GaAs | Cheapest form — synthesised charge for crystal growth and low-cost thick IR blanks; grain boundaries scatter light and reduce strength, so not for high-power laser optics. | 55 | 0 | 590 HV | 48 W/m·K | |
SI-LECDefault Semi-insulating single crystal, liquid encapsulated Czochralski | Standard undoped semi-insulating crystal for CO2-laser windows, IR optics and microwave/MMIC substrates. | 70 | 0 | 600 HV | 55 W/m·K | |
Si-doped conductive single crystal | Conductive substrate grade for LEDs, laser diodes and solar cells; not used for IR windows because free-carrier absorption kills 10.6 µm transmission. | 72 | 0 | 620 HV | 45 W/m·K | |
Semi-insulating single crystal, vertical gradient freeze | Pick when low dislocation density (EPD <5×10³ cm⁻²) and low residual stress matter — epi-ready device substrates and large low-wavefront-distortion optics. | 80 | 0 | 600 HV | 55 W/m·K |
What is GaAs?
GaAs is a III-V semiconductor single crystal with high strength and low absorption at 10.6 µm, supplied as semi-insulating LEC and VGF material, n-type (N-GAAS) and polycrystalline blanks. Engineers use it for CO2 laser optics and IR windows where more mechanical strength and better thermal conductivity (55 W/m·K) than ZnSe are needed, and as a substrate for optoelectronic and laser-diode epitaxy. Limits are {110} cleavage, machinability of 35, a 460 °C service ceiling, about 28% reflection per uncoated surface, and arsenic-dust handling controls. ZnSe remains the alternative where visible-light alignment is required. GaAs has a density of 5.32 g/cm³ (0.192 lb/in³), heavier than 92% of glass grades. It melts at 1,238°C (2,260 °F). GaAs has a tensile strength of 70 MPa (10.2 ksi), stronger than 76% of glass grades. Elongation at break is 0% and the elastic modulus is 85.5 GPa (12.4 Msi).
What is GaAs used for?
- CO2 laser optics
- IR windows/lenses
- optoelectronic device substrates
- laser diode substrates
Advantages
- Conducts heat well — 55 W/m·K (31.8 BTU/hr·ft·°F), better than 93% of glass grades
- Easy to machine — 35/100, better than 77% of glass grades
Limitations
- High embodied carbon — 130 kg CO₂/kg, worse than 97% of glass grades
- Heavy — 5.32 g/cm³ (0.192 lb/in³), worse than 92% of glass grades
- Low fracture toughness — 0.44 MPa·√m (0.4 ksi·√in), worse than 78% of glass grades
GaAs properties
Typical room-temperature values for GaAs-SI-LEC; bars are the position among glass grades.
Physical5
GaAs has a density of 5.32 g/cm³ (0.192 lb/in³), heavier than 92% of glass grades. It melts at 1,238°C (2,260 °F).
Mechanical13
GaAs has a tensile strength of 70 MPa (10.2 ksi), stronger than 76% of glass grades. Elongation at break is 0% and the elastic modulus is 85.5 GPa (12.4 Msi).
Thermal5
GaAs is rated for continuous service to 460°C (860 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), better than 93% of glass grades. Thermal expansion is 5.7 µm/m·K (3.17 µin/in·°F).
Electrical5
GaAs is an electrical insulator with a dielectric strength of 40 kV/mm (1,016 V/mil) and a resistivity of 1,000,000 Ω·m.
Chemical & Environmental2
Corrosion resistance is good (55/100), worse than 74% of glass grades.
Sustainability4
Producing a kilogram of GaAs takes about 2,000 MJ of energy and emits 130 kg of CO₂ — more than 97% of glass grades. Typical recycled content is 5%.
Manufacturability2
GaAs's machinability is fair (35/100, better than 77% of glass grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the glass family
Yield strength against density for every glass grade FabDigit runs. GaAs is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GaAs
Is GaAs easy to machine?
Diamond wire saw / ID saw and diamond lapping only; single-point diamond turning works in ductile regime, but {110} cleavage means edge chipping — always chamfer and use full arsenic-dust extraction.
Can GaAs be welded?
Not weldable; joined by optical contacting, epoxy/indium bonding or metallised (AuGe/Ni/Au) soldering into mounts.
Can GaAs be formed, bent or molded?
No plastic forming — shape is set by melt growth (LEC/VGF) followed by slicing, grinding and polishing; complex profiles are ground, not pressed.
GaAs chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Gastoichiometric 1:1 atomic with As | 48 – 48.4 | 48.2 |
| Cresidual carbon ~1×10¹⁵–1×10¹⁶ cm⁻³, compensates EL2 in SI material | ≈ 2×10⁻⁸ | 2×10⁻⁸ |
| Siintentional dopant only in n-type grade (1×10¹⁷–5×10¹⁸ cm⁻³) | ≈ 1×10⁻⁷ | 1×10⁻⁷ |
| Asmelt grown near-stoichiometric; slight As-rich melt typical | ≥ 51.6 (balance) |
What surface finishes work on GaAs?
CMP to epi-ready/laser-grade finish, then multilayer AR coating (ThF₄/ZnSe or DLC) is essential since each uncoated surface reflects ~28%.
How much does GaAs cost?
GaAs is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GaAs — frequently asked
What is GaAs used for?
GaAs is typically used for CO2 laser optics, IR windows/lenses, optoelectronic device substrates and laser diode substrates. In short: rugged 10.6 µm window; stronger than ZnSe; semi-insulating IR substrate.
What is the tensile strength of GaAs?
GaAs has a typical tensile strength of 70 MPa (10.2 ksi) — stronger than 76% of glass grades. Strength varies by condition: see the 4 listed tempers.
Is GaAs easy to machine?
Not especially — machinability is rated fair (35/100, better than 77% of glass grades). Diamond wire saw / ID saw and diamond lapping only; single-point diamond turning works in ductile regime, but {110} cleavage means edge chipping — always chamfer and use full arsenic-dust extraction.
Can GaAs be welded?
Not weldable; joined by optical contacting, epoxy/indium bonding or metallised (AuGe/Ni/Au) soldering into mounts.
What surface finishes work on GaAs?
CMP to epi-ready/laser-grade finish, then multilayer AR coating (ThF₄/ZnSe or DLC) is essential since each uncoated surface reflects ~28%.
Can GaAs be formed, bent or molded?
No plastic forming — shape is set by melt growth (LEC/VGF) followed by slicing, grinding and polishing; complex profiles are ground, not pressed.
What is the maximum service temperature of GaAs?
GaAs is rated for continuous use to about 460°C (860 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does GaAs cost?
GaAs is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- NSM Archive — Physical Properties of Gallium Arsenide — Ioffe Institute (2001)
- Gallium Arsenide (GaAs) Optical Material Data — Crystran Ltd (2023)
- Handbook of Optical Constants of Solids — Academic Press (Palik, ed.) (1998)
- Semi-Insulating GaAs Substrate Specification (LEC / VGF) — Freiberger Compound Materials / AXT Inc. (2023)
- ASM Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.