Physics of Semiconductor Devices

Metal, semiconductor, insulator

(a) What is the difference between a metal, a semiconductor, and an insulator? Discuss the Fermi energy when describing this difference.

(b) The band structure of a semiconductor is shown below. Describe how you could determine the effective mass of the holes from this diagram. Does this semiconductor have a direct or indirect bandgap? What frequency would a photon need to generate an electron-hole pair in this semiconductor?