Contents
What is drift in semiconductor?
Drift is, by definition, charged particle motion in response to an applied electric field. When an electric field is applied across a semiconductor, the carriers start moving, producing a current. Drift current in a semiconductor is the resultant of carrier drift.
What are drift and diffusion currents?
Difference between Drift Current and Diffusion Currents
| Drift Current | Diffusion Current |
|---|---|
| This current obeys Ohm’s Law. | This current obeys Fick’s Law. |
| The direction of charge carriers in the semiconductor is reverse to each other. | For charge carriers, the densities of diffusion are reverse in symbol to each other. |
What is drift process?
As seen previously, an electron moving in a crystal lattice moves just like a free electron, but with a change of mass. This fact justify us to use the classical equations of motion, in order to describe the motion of electrons and holes in a semiconductor device.
How are drift and diffusion currents related in semiconductors?
Drift and diffusion are responsible for generating current in semiconductors and the overall current density is the sum of the drift and diffusion currents. Drift current arises from the movement of carriers in response to an applied electric field.
Why is the movement of charge carriers known as drift current?
The movement of charge carriers is because of the applied electric field is known as drift current. The diffusion current can be occurred because of the diffusion in charge carriers. It requires electrical energy for the process of drift current.
Which is an important process in the semiconductor?
But the overall current density is the sum of the drift and diffusion currents. The drift and the diffusion both are the important process occurred in the semiconductor once the doping is done.
How is diffusion current related to concentration gradient?
The diffusion current is proportional to the concentration gradient or how nonuniformly the carriers were initially distributed. Since the carriers are diffusing from areas of higher concentration to areas of lower concentration, +q is assigned for electrons and -q is assigned for holes in the equation for the current density.