Q:- A current of (2 HA) passing through an intrinsic silicon bar has (3 mm) length and (50 x 100 um?) cross section area. The resistivity of the bar is (2.3 x 10 0/cm) at (300 K) find the voltage across the bar?

a) Explain the band structure of an electrical conductor (metal), a semiconductor, and an insulator at 0 K by showing the valence and conduction bands and fermi energy levels. Explain how the electrical conduction takes place in these three types of materials. Give an example for each type of material. b)Explain what n and p-type semiconductors are using their band structures.

A picce of p-type silicon with a cross section of I mm x 1 mm and length of 10 mm has i resistivity of 10 0-m at 27°C. Ohmic contacts are fabricated on the surfaces at either end of the longest dimensions of the bar and a DC voltage of 10V is applied, Assuming a hole mobility uh -0.03 m/V-s, calculate: The impurity concentration The velocity of the carriers through the bar The time taken for carriers to transverse across the bar The magnitude of the current in bar iv)

Using the idea of energy bands in solid materials, explain the characteristics of the followingmaterialsa) conductorsb) insulatorsc) semiconductors