Week 2: PN Junction Diode

Reverse-Biased PN Junction
Reverse biasing means applying an external voltage v D < 0:
• Built-in potential increases/barrier increases;
• Majority electrons and holes can hardly cross the junction
– Diffusion decreases
• Drift current almost unchanged as there are little supply of carriers
(minorities).
∴ i D = I diffusion –I drift < 0 and tends to –I drift .
ELE2110A © 2008
Lecture 02 - 13