2.7. MOBILE CARRIERS 59
1017
1016
1015
1014
1013
1012
1011
1010
109
108
107
106
1000 500 200 100 27 0 –20
T ( ̊C)
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
1000/T (K–1)
Ge
Si
GaAs
INTR INSIC
CARRIER
DENSITY
ni
(cm
–3
)
GaN
105
104
Lowest measured unintentional carrier
concentration in GaN.
Figure 2.18: Intrinsic carrier densities of Ge, Si, GaAs, and GaN as a function of reciprocal
temperature. Currently, the lowest measured unintentional background density in GaN at room
temperature is around 1 × 1015 cm−^3 , indicating that the electronic properties are dominated by
defects (either extrinsic or intrinsic point defects).