Question

Select the correct statement.
1. At 1 kV/cm, the velocity of electrons in GaAs is less than the velocity of electrons in Si.
2. At 1 kV/cm, the velocity of electrons in GaAs is less than that of electrons in diamond.
3. At 1 kV/cm, the velocity of holes in GaAs is less than the velocity of holes in Si.
4. At 1 kV/cm, the velocity of holes in diamond is less than the velocity of holes in Si.

Answer 1

Correct Answer - Option 3 : At 1 kV/cm, the velocity of holes in GaAs is less than the velocity of holes in Si.

The electrons’ mobility in GaAs is much larger (> 6 times) than electrons’ mobility in Si.

But the holes’ mobility is similar in both materials, in fact, it is a little lower in GaAs.

Property	Si	GaAs
Bandgap (eV)	1.12	1.4
Breakdown Field (MV/cm)	0.25	0.4
Saturation Drift Velocity (107 cm/s)	1	2
Max. Operating Temperature (C)	350	460
Electron Mobility (cm2/V-s)	1350	8500
Hole Mobility (cm2/V-s)	480	400
Static dielectric constant	11.8	12.8