Comment Re:"conducts electrons 1,000 x faster than silicon (Score 1) 91
Essentially electrons in crystalline materials (which GaN and Si are) behave "quantumly". This can lead to weird effects such as an electron appearing to be heavier or lighter than you would expect depending on the material. Another property is the speed at which the average electron appears to be moving (drift velocity) when a given electric field (E) is applied. Mobility is simply dv/dE which ideally is linear (isn't the case at high E). The crystallinity of a material is important to this value. Graphite and carbon are both allotropes of carbon yet have different mobilities.
GaN seems to have a higher electron mobility than silicon (~10,000 vs 1,200 cm^2/Vs for undoped GaN and Si respectively). This is only a 10x difference so I'm not quite sure where they get the 1000 figure. If you take a piece of GaN and apply 1V 1 cm apart the electrons would move at 10k cm/s while in silicon would only move 1.2k cm/s. Faster electrons allow you to shrink transistors and achieve the same current. For example faster water flow allows you to use a smaller hose to deliver water to the destination at the same rate.