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Dr. Manoj
- 20
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What exactly is difference between diffusion current and drift current?
Drift is due to an applied force while diffusion is only because of the concentration gradient of particles. Particles move from the region with high concentration to anywhere with lower concentration with no force.OmegaKV said:Drift is when electrons move in response to the electric field from an applied voltage source. Diffusion is when electrons move in response to the electric field from other electrons/holes in the semiconductor.
Diffusion is not in response to any electric filed. It is only caused by concentration gradient.OmegaKV said:Diffusion is when electrons move in response to the electric field from other electrons/holes in the semiconductor.
A PN junction diode is a type of semiconductor device that has two layers of doped semiconductor material, one with an excess of electrons (N-type) and the other with a deficiency of electrons (P-type). The junction between these two layers creates a barrier for current flow, which can be manipulated by applying a voltage to the diode.
Diffusion current is the flow of charge carriers (electrons and holes) from a region of higher concentration to a region of lower concentration. In a PN junction diode, this occurs due to the natural movement of charge carriers across the junction, from the N-type region to the P-type region.
Drift current is the flow of charge carriers due to an applied electric field. In a PN junction diode, this occurs when a voltage is applied to the diode, creating an electric field that causes the charge carriers to move in a specific direction.
The main difference between diffusion and drift current in a PN junction diode is the cause of the current flow. Diffusion current is due to the natural movement of charge carriers, while drift current is a result of an applied electric field. Additionally, diffusion current is dependent on the concentration gradient of charge carriers, while drift current is dependent on the strength of the applied electric field.
The balance between diffusion and drift current determines the overall current flow through a PN junction diode. When the diode is forward biased (positive voltage applied to the P-type side and negative to the N-type side), the drift current dominates and the diode conducts electricity. When the diode is reverse biased, the diffusion current dominates and the diode does not conduct electricity. This allows PN junction diodes to be used as rectifiers, allowing current flow in only one direction.