An explanation of the principles of a pn junction is proposed without recourse to the band model, the space charge of the junction, and the charge carrier depletion at the interface. The explanation assumes that the processes in a pn junction can be considered as a chemical reaction between electrons, holes, and photons and that an -type material is a conductor for electrons and an insulator for holes, and a -type material is a conductor for holes and an insulator for electrons. We give a simple and concise explanation of rectification, light emission, and current generation by pn junctions.
REFERENCES
1.
P. A.
Tipler
and G.
Mosca
, Physics for Scientists and Engineers
(Freeman
, New York, 2004
), pp. 1248
–1250
.2.
3.
4.
5.
6.
In addition to the reaction with photons in Eqs. (1)–(3) there is a similar reaction with phonons (non-radiative transitions). This contribution to the reaction increases the reaction rates in both directions but leaves the concentrations unaltered. Our treatment of the pn junction is therefore not restricted to the ideal case where all transitions are radiative.
© 2006 American Association of Physics Teachers.
2006
American Association of Physics Teachers
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