The resistivity of a semiconductor can be modified by

Chapter 25, Problem 25.77

(choose chapter or problem)

The resistivity of a semiconductor can be modified by adding different amounts of impurities. A rod of semiconducting material of length L and cross-sectional area A lies along the x-axis between x = 0 and x = L. The material obeys Ohms law, and its resistivity varies along the rod according to r1x2 = r0 exp1-x>L2. The end of the rod at x = 0 is at a potential V0 greater than the end at x = L. (a) Find the total resistance of the rod and the current in the rod. (b) Find the electric-field magnitude E1x2 in the rod as a function of x. (c) Find the electric potential V1x2 in the rod as a function of x. (d) Graph the functions r1x2, E1x2, and V1x2 for values of x between x = 0 and x = L