Question

Can the potential barrier across a p-n junction be measured by simply connecting a voltmeter across the junction ?

Answer 1

No , potential barrier across a p-n junction cannot be measured by simply connecting a voltmeter across the junction.

• In P-N junction diode , the electrons from N- region diffuse through the junction into N - region.

•Due to diffusion a layer of negative charged ions appear near the junction in the P-crystal and a layer of positive ions appear near the junction in N - crystal . This layer is called depletion region or layer.

• The potential difference created across depletion region due to diffusion of electrons and holes is called potential barrier.

For eg. for Ge V = 0.3V

•Voltmeter tells voltage between two terminals .So, it can't tell in built barrier potential of diode.