In forward bias, the positive terminal of the battery is connected to the p-side and negative to the n-side.

• The applied voltage opposes the built-in barrier potential ($V_0$).
• This reduces the width of the depletion layer and the effective barrier height $(V_0-V)$.
• As a result, many more majority carriers (holes from p, electrons from n) gain enough energy to cross the junction, resulting in a large current that increases exponentially with voltage.