Pn Junction under Forward and Reverse Bias - Energy band diagram and drift & diffusion currents

Oct 29, 2026

Upload by Franzy

Explains the physics of a PN junction under forward and reverse bias using energy band diagrams. Describes how applied potential changes the carrier energy landscape, leading to depletion-region behavior and different current components. Compares forward-bias conditions where drift and diffusion contributions combine to produce significant carrier injection, with reverse bias where current remains small and governed by minority carriers. Summarizes the role of electric-field and space-charge effects in shaping carrier transport, potential drop, and junction depletion characteristics.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages8

Reading Time20 min

AccessFree to download

Pn Junction under Forward and Reverse Bias: Energy band diagram and drift & diffusion currents

Forward-bias analysis and carrier energy changes

Reverse-bias behavior and depletion region effects

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FAQs

How does forward bias affect the PN junction energy bands?

Forward bias reduces the effective barrier and changes the potential distribution across the depletion region, enabling carriers to move across the junction more readily.

What determines the current components in a PN junction?

The current results from the combined influence of drift due to the electric field and diffusion due to carrier concentration gradients, with their balance depending on the bias condition.

Why is reverse-bias current typically much smaller than forward-bias current?

Reverse bias increases the effective barrier and widens the depletion region, so transport is largely limited to minority carriers rather than significant carrier injection across the junction.

Oct 29, 2026

Upload by Franzy