In a junction diode how much is junction current at equilibrium without any applied external voltage
Answers
Ideally there is no current under equilibrium condition with no external bias.Asyou mentioned that there is no external excitation ,so when you connect the ammeter to measure the current in the diode , the metallic wires from the ammeter terminal & the semiconductor body as come in contact, it causes a built-in potential at this metal -semiconductor contact (Schottky Junction) and these built in potentials will cancel the built-in potential due to p-n junction.This cancellation causes no current in the loop as there is no voltage source.
From conservation of energy point of view:
As there is no external supply and in such a case, if there is presence of current i.e. electric power.It violates the law of conservation of energy. Hence there will be no current.