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physics.cie
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Why energy level is higher on p side of pn junction diode as compare to n side of same
A pn junction is a type of semiconductor junction formed by bringing together a p-type semiconductor (having positively charged carriers) and an n-type semiconductor (having negatively charged carriers). This junction creates a depletion region at the interface where electrons and holes recombine, resulting in a potential barrier.
The energy level in a pn junction determines the direction and magnitude of the flow of charge carriers. In an equilibrium state, the energy levels are balanced, resulting in no net flow of charge. However, when a voltage is applied, the energy levels become imbalanced, allowing for the movement of charge carriers across the junction.
The band gap in a pn junction is the difference in energy levels between the conduction band (where electrons can move freely) and the valence band (where electrons are bound to atoms). This band gap is responsible for the creation of the depletion region and the potential barrier in a pn junction.
The doping level (concentration of impurity atoms) in a pn junction determines the width and intensity of the depletion region. Higher doping levels result in a thinner depletion region and a lower potential barrier. Lower doping levels result in a wider depletion region and a higher potential barrier.
In forward bias, the applied voltage is in the direction of the potential barrier, allowing for the movement of charge carriers across the junction. In reverse bias, the applied voltage is in the opposite direction of the potential barrier, preventing the movement of charge carriers and resulting in a wider depletion region.