Question

4. A p-type semiconductor has positive charge carriers but is electrically neutral. Similarly an n-type semiconductor has negative charge carriers but is electrically neutral. When they are put in contact (making a diode), statistical forces cause some of the charge carriers to migrate to the opposite semiconductor. The charge carriers move until an E-field is created to stop the migration. This E-field creates a depletion region near the junction where there are no charge carriers. If a forward voltage is applied to the diode, the voltage needs to be large enough to move charge carriers back into the depletion region before and current can flow through the diode. If a backward voltage is applied to the diode, that voltage just increases the depletion region and no significant current flows. Are these statements about the PN junction in a diode true or false? a) Electrons from the p-region diffuse across the junction into the n-region b) An electric field is created in the region of the junction. c) In the region around the junction there are very few holes in the P region. d) There is a voltage drop across the junction that opposes current in the forward direction of the diode

Answer 1

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L4) This is talse because electarons frem n - differse aco ss the juuctiou into Ha Pegion because elechon s majai ty charze carvies n sane 3 a stes fro m the p-egim diffuse. across Hhejun cthaw iuto ths toe canse hstes are. majandy charye carriens for p-negicn b) Troue An electric field is sat up across te junchow from posti ve changa region edside of jun chios to nepalive change regon an p-side jundhen false Dn tha P- region hetes ame (C) (d) Toue Yes thure is a potenhal daop ac oss tha funehiow wbich opposes currenl in tor wasd di ve chien of tha diode