The electron concentration nx and the direction of the elect

The electron concentration n(x) and the direction of the electric field E in a semiconductor arc shown below. Clearly indicate the direction of the current due to drift and the current due to diffusion, and explain.

Solution

Diffusion is due to concentration gradient , concentration of electrons are more on right hand side so electrons move from right to left so diffusion current direction is from left to right .applied electric field direction is left to right, electron direction is always opposite to direction of electric field so drift current direction is from left to right .Both drift and diffusion currents are in the same direction that is from left to right