N-type germanium is a form of germanium semiconductor that has been intentionally doped with donor impurities to introduce an excess of free electrons, which become the majority charge carriers. This controlled introduction of impurities—known as doping—modifies the electrical properties of the material without significantly altering its fundamental optical characteristics.
Common dopants for N-type germanium include phosphorus, arsenic, and antimony. These elements possess five valence electrons, compared to germanium’s four. When incorporated into the germanium crystal lattice, the extra valence electron becomes weakly bound and is easily available for electrical conduction.
| Parameter | Typical Range |
|---|---|
| Crystal Type | Single Crystal / Polycrystalline |
| Diameter | 12 mm – 380 mm |
| Length | Customizable |
| Electrical Resistivity | ~0.005 – 50 Ω·cm |
| Purity | 99.999% – 99.9999% |
| Conduction Type | N-type / P-type |
| Surface Roughness | Ra max 0.2 µm to 4.0 µm |
| Refractive Index (10.6 µm) | 4.005 |
| Absorptance (10.6 µm) | ≤ 0.035 |
Note: Infrared transmission performance is primarily governed by resistivity, thickness, and coating design rather than conduction type alone.