Why potential of n side is higher in unbiased p-n junction

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In an unbiased p-n junction, the n-side exhibits a higher potential than the p-side due to the diffusion of charge carriers, which creates a net positive charge in the n-type material and a net negative charge in the p-type material. This charge separation results in a potential barrier that prevents further diffusion of carriers, establishing a voltage across the junction. When no external battery is connected, there is no current flow, and the potential difference is primarily due to the built-up charges rather than an applied voltage. The potential difference typically requires a forward bias (around 0.7V for silicon) to allow current to flow. Thus, the higher potential on the n-side indicates it is more positively charged compared to the p-side.
Rishav sapahi
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why the potential of n side is higher than that of the p side when no battery is connected to the p-n junction?
 
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Well if there is no battery, the circuit is pretty much useless... The p-n junction is typically associated with a voltage drop across the p-n junction (somewhere around .5-3V for LEDs). However with no battery in the circuit, there will be no current flowing and thus no voltage across the junction, so they should be at the same potential.
 
but in my book they are stating that n-side is at higher potential without any explanation
 
Is the battery attached to the n-side? If so, then yes, the n-side would be at a higher potential and the p-side would be a 0V, since there in no (practically none) current flowing through the diode. This is known as the reverse-bias direction. The voltage at the n-side would be at the same voltage as the battery (assuming it is just connected with a wire).
 
Look up "PN junction depletion region". The natural potential that develops spontaneously across a PN junction is due to the diffusion of charge carriers across the junction. P type material has "holes" in its bond structure that can be "filled" by accepting electrons, while the N side has more than enough conduction electrons to satisfy its bond requirements.

However, every electron that crosses over leaves a small net positive charge in the N material, while the P side gains a small negative charge. These charges build up until they suppress further movement --- they raise a potential barrier against further diffusion of charges. This is what leads to the "turn on" bias requirement to get current moving across the junction (about 0.7V for silicon PN junctions).
 
so Is high potential just means that given side is more positively charged than other
 
Rishav sapahi said:
so Is high potential just means that given side is more positively charged than other

Yes. A potential develops across the junction.
 

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