(a) What is scattering and how it effects the current flow in a semiconductor material? (b) Name two important types of scattering mechanisms discussed in this class and explain their

origin. (c) Which type of current, drift or diffusion, is affected by scattering events? (d) Define the following parameters (1) momentum relaxation time, (2) mobility and (3) conductivity for a semiconductor? Write equations that draw relations between a. mobility and relaxation time,b. velocity and applied electric field,c. current density and applied electric field having the parameter mobility,d. current density and applied electric field having the parameter conductivity. (e) A Si-bar is doped with 1017 phosphorous atoms per cu. em.Measurement has revealed that the carrier-drift velocity and electric field follow the relation shown in the figure on the right. Find out mobility, conductivity and resistivity of the sample for a. applied field is =10^3 V/cm b. applied field is = 10^5 V/cm