Gallium Arsenide (GaAs) is a dark gray crystal with a metallic luster that serves as a very important optical material. This material is widely used in far-infrared infrared optics, optoelectronics, and microelectronics. Alfa Chemistry can use GaAs crystal material to custom fabricate optical components of virtually any shape and size to customer requirements. If you need help, please contact us.
Advantages and Uses of Gallium Arsenide Materials
GaAs crystals can be grown by liquid encapsulated Czochralski (LEC) technique, floating zone (FZ) method, vertical gradient freezing (VGF), and horizontal gradient freezing (HGF) techniques. GaAs doped crystals are employed in numerous applications. Their characteristics are largely influenced by how the dopant interacts with the inherent crystal flaws. Highly silicon-doped crystals are utilized in laser diodes, LEDs, photocathodes, and RF generators.
Fig 1. Transmission spectrum of GaAs. (Dushkina N. M, et al. 2002)
In microelectronic applications, GaAs is mostly non-doped semi-insulating material. Notably, only non-doped semi-insulating GaAs is used in optics. Non-doped semi-insulating GaAs is highly transmissive in the THz range (λ=100-3000 μm) and the mid-infrared region between 1 and 15 μm. GaAs can be used in lenses and beam splitters, and it can replace zinc selenide in low-power CO2 lasers operating at wavelengths between 9.6 and 10.6 μm. GaAs crystals can be employed as terahertz radiation generators in terahertz photonics because of their nonlinear optical characteristics. In addition, GaAs can also exhibit linear electro-optical effects (Pukels effect). Under the influence of an external electric field, the material's refractive index changes. The crystal becomes optically anisotropic in the presence of an external electric field. The refractive index of light polarized parallel to the electric field changes.
Properties of Gallium Arsenide Materials
| Density | 5.315 g/cc |
| Molecular Weight | 144.64 |
| Solubility | Insoluble in water |
| Class/Structure | Cubic ZnS, F43m, (100) cleavage |
| Melting Point | 1511°C |
| Hardness | Knoop 750 |
| Refractive Index | 3.2727@10.33 μm |
| Transmission Range | 1 to 16 μm |
| Reflection Loss | 44%@10.33 μm |
| Apparent Elastic Limit | 71.9 MPa |
| dn/dT | 147x10-6/°C@10 μm for derivation |
| Youngs Modulus (E) | 84.8 GPa |
| Bulk Modulus (K) | 75.5 GPa |
| Thermal Expansion | 5.7x10-6 /°C at 300K |
| Thermal Conductivity | 48 W/m/K @ 273K |
| Dielectric Constant | 12.91 at low frequencies |
| Specific Heat Capacity | 360 J Kg-1 K-1 |
| Absorption Coefficient | 0.01 cm-1 |
| Poisson Ratio | 0.31 |
About refractive index parameters.
"No" means ordinary light.
| µm | No | µm | No | µm | No |
|---|---|---|---|---|---|
| 1.033 | 3.492 | 1.550 | 3.3737 | 2.066 | 3.338 |
| 2.480 | 3.324 | 3.100 | 3.3125 | 4.133 | 3.3027 |
| 4.959 | 3.2978 | 6.199 | 3.2921 | 7.293 | 3.2874 |
| 8.266 | 3.2831 | 9.537 | 3.2769 | 10.330 | 3.2727 |
| 11.270 | 3.2671 | 12.400 | 3.2597 | 13.780 | 3.2493 |
Reference
- Dushkina N. M, et al. (2002). "Dicing of Gallium Arsenide (GaAs) Wafers with The Laser MicroJet® Challenges, Improvements and Safety Issues." ICALEO 2002. 851160.