Problem
In an n-type semiconductor bar, there is an increase in electron concentration from left to right and an electric field pointing to the left.
1. With a suitable sketch, indicate the directions of the electron drift and diffusion current flow and explain why.
2. If we double the electron concentration everywhere, what happens to the diffusion current and the drift current?
3. If we add a constant concentration of electrons everywhere, what happens to the drift and diffusion currents? Explain your answers with appropriate equations.