(For these problems use typical room temperature bulk Si hole and electron mobilities: hole -> 460 cm^2/V-sec and electron -> 1360 cm^2/V-sec)

1. A Si wafer is doped with Na = 5x10^16 /cm^3 of acceptors. In equilibrium at T=330K calculate, list the following for the Si wafer: Eg (Energy gap), ni (intrinsic concentration), n,p - the free electron and hole concentrations, Ef - Ei (in eV), the net charge density in the sample, the resistivity of the sample

2. The resistivity of comparably doped N type material is smaller than comparably doped p-type material. Explain?

3. Calculate the resistivity of intrinsic Si and room temp T=300K

4. The total resistance of a Si sample shaped as a rectangular bar is given by R = p* L / A where L and A are the length and cross-sectional area of the sample and the resistivity. If you need to make a 600 ohm resistor from n N type Si sample that is 2 cm long and has a cross sectional area of 10-2 cm^2 determine the doping required.