0
$\begingroup$

In the forward bias when electrons enter the p-type region of the semiconductor, the charge concentration is increased, and since the movement of electrons is faster than the movement of holes, it ends up with no charge concentration difference. How is this possible and why it seems to stop current?

$\endgroup$
  • 1
    $\begingroup$ I'm confused about the situation you are asking about. Forward bias means drift current exists as well. But I think your confusion relates to the junction region - electrons come in from one side, holes from the other, and they annihilate each other there. (Electrons moving faster than holes has little to do with this, and may not apply to all semiconductors.) $\endgroup$ – Jon Custer Feb 4 at 13:48
  • $\begingroup$ P type semiconductor has less charge concentration than the N type and conductor . In forward bias the voltage barrier between the 2 junctions is very reduced so electrons can easily diffuse from n type region to p type region.While the free electrons travel through the diode they end up in the p type region where the increase the charge concentration of the p type region and because holes move slower than the free electrons the total charge concentration is increased and electrons stop diffusing? $\endgroup$ – Max Destiny Feb 4 at 14:02
  • $\begingroup$ Where I wrote and conductor is semiconductor $\endgroup$ – Max Destiny Feb 4 at 14:02
  • $\begingroup$ No, they die in the p region, taking a hole with them. And, one can certainly have p regions with higher doping than n regions. Electrons won't last long in a p-type region (which is the reason bipolar transistor bases have to be relatively thing). $\endgroup$ – Jon Custer Feb 4 at 14:13
  • $\begingroup$ Even if they die a hole and an electron neutralize each other and now that atom has 4 outer electrons so the electron concentration is increased $\endgroup$ – Max Destiny Feb 4 at 14:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.