Question

3. Draw the I-V characteristics of a solid composed of: (a) an n-type semiconductor (b) a p-type semiconductor (c) a p-n junction (with current flowing through the junction) (d) Briefly explain in words why the p-n junction I-V characteristics differ from those of the n- and p-type materials alone.

Answer 1

Semiconductor lotrensic Semiconductor (PURE FORM) Extrencic SEMICONDUCTOR [" A SEMICONDUCTOR CERTAIN IMPURITIES ADDED] * This process is known as Doping ENEROY BAND DIBORAN) OF SEMICONDUCTOR ConducTION BAND Eu Nlev VALANCE BAND Qan semiconductor type A Silicon doped with penta ualent impurity (Ey :- Arsenic) The pentavalent has five electrons in their bod. Talance band Outermost orbit of which four form co valent bond with her four adjecent si atom. The fifth electron can not foom a co valent bond, it is free and requires Verry litile energy to free itself from the attractive force of nucleous. Phis of free electron Galleel is prensent when silicon doped with postavalent impurities Hence it is called entype semiconduter excess

I Cult in vollage Break dwon. d). Pan junction in type Pype Silicon silicon Anode Cathode. Anode cathode A A a po junction, the ckt Symbol is shown, po junction is boundary of or interface between 16oo types of semiconductor materials, p type and excess of holes, while inside (negative) contains excess of electrons. This allows electrical current pass through the sunition only one direction type side contains to

characteristics of a type Cugat (D. 1 5 5 10 10: vollage CV) P side ac oss is to Po junction this current flowing through junction) under forward biased (p side to tive of the cell, worit aside to negative) the holes are injected from the the depletion region. n-side Near the depleton region minority concentration about the thermal equilibrium Concestoration because of the ese electricaly injected holes process diffusion & recombination. electros bole the mi came There are two N → P N Р holes 00 0 0 + toward Reverese depletion cregion.