Table 1.
Physical properties of ZnO with the wurtzite structure. Data were derived from literature [98,99,100,101,102,103,104,105,106,107].
| Properties | Value |
|---|---|
| Molecular formula | ZnO |
| State (colour, form) | white powder |
| CAS Reg No. | 314-13-2 |
| Molar mass | 81.39 g/mol |
| Density at room temperature | 5.606 g/cm3 (crystal theoretical density 5.61 g/cm3) |
| Solubility in water (25 °C) | 1.6 mg/L |
| Melting point | 1975 °C |
| Boiling point | 2360 °C |
| Stable phase at room temperature | wurtzite |
| Structure | Hexagonal, where a0 = b0 ≠ c0 |
| Space group symmetries | C4 6v (P63mc) |
| Bulk effective piezoelectric constant | 9.9 pm/V |
| Hardness | 5.0 ± 0.1 GPa |
| Lattice parameters at 300 K | |
| a 0 | 3.2495 Å |
| c 0 | 5.2069 Å |
| c0/a0 | 1.602 (ideal hexagonal structure shows 1.633) |
| U | 0.345 |
| Thermal conductivity | 0.6, 1–1.2 W·cm−1·K−1 |
| Specific heat | 0.125 cal/gm·°C |
| Linear expansion coefficient | a0: 6.5 cm 3 × 10−6 K |
| c0: 3.0 cm 3 × 10−6 K | |
| Static dielectric constant | 8.656 ε(0), ε(∞) |
| Thermoelectric constant at 573 K | 1200 mV/K |
| Refractive index | 2.008–2.029 |
| Band gap | at RT: 3.370 eV |
| at 4 K: 3.437 eV | |
| Exciton binding energy | 60 meV |
| Intrinsic carrier concentration | <106 cm3 |
| Electron effective mass | 0.24 m0 |
| Hole effective mass | 0.59 m0 |
| Electron Hall mobility at 300 K | 200 cm2/V·s |
| Hole Hall mobility at 300 K | 5–50 cm2/V·s |
| Ionicity | 62% |