p-n Junction Diodes

Instructor S. Demlow ECE 410 January 20, 2012

Depletion Region when a p-type and n-type semiconductor region are brought together, carriers to diffuse across the junction to recombine with dopants, leaving behind ionized cores. An electric field is set up by the charge distribution, opposing the process until an equilibrium is reached

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Diffusion Recombination leaves ion cores

Ion cores repel additional charges from diffusing at equilibrium

Depletion Region when a p-type and n-type semiconductor region are brought together, carriers to diffuse across the junction to recombine with dopants, leaving behind ionized cores. An electric field is set up by the charge distribution, opposing the process until an equilibrium is reached

hyperphysics

Bias An applied bias with positive voltage on the p-side and negative on the n-side will allow carriers to overcome the coulomb forces of the space charge in the depletion region. A Reverse bias will further oppose carrier entry into the depletion region.

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Forward Bias Reverse Bias

Current Flow An applied bias with positive voltage on the p-side and negative on the n-side will allow carriers to overcome the coulomb forces of the space charge in the depletion region, and current will flow with a small resistance. A Reverse bias will further oppose carrier entry into the depletion region, and current will be blocked, except for a small leakage current.

hyperphysics

Forward Bias Reverse Bias