1. A Si sample is doped simultaneously with 10¹⁸ cm^-3 donors and with 5 x 10¹⁷ cm^-3 acceptors. What is the equilibrium concentration of:

1. electrons,

2. holes.

3. What is the position of E_F with respect to E_i ?

2. For intrinsic Si, the conductivity effective masses are: 0.26m_o for electrons and 0.386 m_o for holes. Using these and the mobility values in Appendix III, find the mean time between carrier scattering events for:

(a) electrons and

(b) holes.

3. Using the mobility values in Appendix III, find the intrinsic resistivity of:

1. Si, using n_i = 1.5 x 10¹⁰ cm^-3,

2. GaAs, using n_i = 1.8 x 10⁶ cm^-3.

4. For Si with a Phosphorus atom impurity concentration of 10¹⁹ cm^-3, find:

1. the electron mobility, using the appropriate Figure in Section 3.4,

2. the hole mobility, using the appropriate Figure in Section 3.4, and

3. your calculated value of the resistivity, using results from (a) and/or (b).