Gallium nitride vs Silicon
Gallium nitride and Silicon are genuine alternatives to one another — a choice somebody actually makes — and differ on 3 measured properties, density most clearly.
Gallium nitride vs Silicon
These are different kinds of thing (compound, element). Fewer properties mean the same thing across both, so a like-for-like reading may not be available.
Gallium nitride
GaN
The semiconductor that made blue light possible, and is now making phone chargers small — a wide band gap, and thirty years of work to grow it on anything.
Silicon
Si
The second most abundant element in the Earth's crust, and the substrate of essentially all modern electronics.
| Property | Gallium nitride | Silicon |
|---|---|---|
| Atomic number Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 14 |
| Crystal system Only one of the two has a figure we can stand behind, so there is nothing to compare. | hexagonal | Not known |
| Density | 6.15 g/cm³ higher | 2.329 g/cm³ |
| Melting point | 2500 °C higher | 1414 °C |
| Molar mass | 83.73 g/mol higher | 28.085 g/mol |
| Refractive index Only one of the two has a figure we can stand behind, so there is nothing to compare. | 2.4–2.5 | Not known |
| Thermal conductivity Only one of the two has a figure we can stand behind, so there is nothing to compare. | 130–230 W/(m·K) | Not known |
Choosing between them
Gallium nitride is recorded as a substitute for Silicon — lighter, better at temperature.
What it gives up: Several times the cost per ampere, and it switches fast enough that the circuit around it has to be designed for the edges — which is why silicon still holds everything that is merely adequate.
In this application, on the evidence cited above.